diff --git a/integration/angular/simple-message.ts b/integration/angular/simple-message.ts
index d0d91053c..7d17c402f 100644
--- a/integration/angular/simple-message.ts
+++ b/integration/angular/simple-message.ts
@@ -54,11 +54,7 @@ export const SimpleMessage = {
 
   fromPartial(object: DeepPartial<SimpleMessage>): SimpleMessage {
     const message = { ...baseSimpleMessage } as SimpleMessage;
-    if (object.numberField !== undefined && object.numberField !== null) {
-      message.numberField = object.numberField;
-    } else {
-      message.numberField = 0;
-    }
+    message.numberField = object.numberField ?? 0;
     return message;
   },
 };
diff --git a/integration/avoid-import-conflicts/simple.ts b/integration/avoid-import-conflicts/simple.ts
index d9679acbc..b06a4bda3 100644
--- a/integration/avoid-import-conflicts/simple.ts
+++ b/integration/avoid-import-conflicts/simple.ts
@@ -117,11 +117,7 @@ export const Simple = {
 
   fromPartial(object: DeepPartial<Simple>): Simple {
     const message = { ...baseSimple } as Simple;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     if (object.otherSimple !== undefined && object.otherSimple !== null) {
       message.otherSimple = Simple2.fromPartial(object.otherSimple);
     } else {
@@ -189,16 +185,8 @@ export const SimpleEnums = {
 
   fromPartial(object: DeepPartial<SimpleEnums>): SimpleEnums {
     const message = { ...baseSimpleEnums } as SimpleEnums;
-    if (object.localEnum !== undefined && object.localEnum !== null) {
-      message.localEnum = object.localEnum;
-    } else {
-      message.localEnum = 0;
-    }
-    if (object.importEnum !== undefined && object.importEnum !== null) {
-      message.importEnum = object.importEnum;
-    } else {
-      message.importEnum = 0;
-    }
+    message.localEnum = object.localEnum ?? 0;
+    message.importEnum = object.importEnum ?? 0;
     return message;
   },
 };
diff --git a/integration/avoid-import-conflicts/simple2.ts b/integration/avoid-import-conflicts/simple2.ts
index 31433569f..8284e539f 100644
--- a/integration/avoid-import-conflicts/simple2.ts
+++ b/integration/avoid-import-conflicts/simple2.ts
@@ -105,16 +105,8 @@ export const Simple = {
 
   fromPartial(object: DeepPartial<Simple>): Simple {
     const message = { ...baseSimple } as Simple;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = 0;
-    }
+    message.name = object.name ?? '';
+    message.age = object.age ?? 0;
     return message;
   },
 };
diff --git a/integration/barrel-imports/bar.ts b/integration/barrel-imports/bar.ts
index a8303f685..3cbfb3b15 100644
--- a/integration/barrel-imports/bar.ts
+++ b/integration/barrel-imports/bar.ts
@@ -65,16 +65,8 @@ export const Bar = {
 
   fromPartial(object: DeepPartial<Bar>): Bar {
     const message = { ...baseBar } as Bar;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = 0;
-    }
+    message.name = object.name ?? '';
+    message.age = object.age ?? 0;
     return message;
   },
 };
diff --git a/integration/barrel-imports/foo.ts b/integration/barrel-imports/foo.ts
index 42307b7e7..78c08c18a 100644
--- a/integration/barrel-imports/foo.ts
+++ b/integration/barrel-imports/foo.ts
@@ -66,11 +66,7 @@ export const Foo = {
 
   fromPartial(object: DeepPartial<Foo>): Foo {
     const message = { ...baseFoo } as Foo;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     if (object.bar !== undefined && object.bar !== null) {
       message.bar = Bar.fromPartial(object.bar);
     } else {
diff --git a/integration/batching-with-context/batching.ts b/integration/batching-with-context/batching.ts
index 00edf4034..1afac519c 100644
--- a/integration/batching-with-context/batching.ts
+++ b/integration/batching-with-context/batching.ts
@@ -358,11 +358,7 @@ export const BatchMapQueryResponse_EntitiesEntry = {
 
   fromPartial(object: DeepPartial<BatchMapQueryResponse_EntitiesEntry>): BatchMapQueryResponse_EntitiesEntry {
     const message = { ...baseBatchMapQueryResponse_EntitiesEntry } as BatchMapQueryResponse_EntitiesEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = '';
-    }
+    message.key = object.key ?? '';
     if (object.value !== undefined && object.value !== null) {
       message.value = Entity.fromPartial(object.value);
     } else {
@@ -418,11 +414,7 @@ export const GetOnlyMethodRequest = {
 
   fromPartial(object: DeepPartial<GetOnlyMethodRequest>): GetOnlyMethodRequest {
     const message = { ...baseGetOnlyMethodRequest } as GetOnlyMethodRequest;
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = '';
-    }
+    message.id = object.id ?? '';
     return message;
   },
 };
@@ -528,11 +520,7 @@ export const WriteMethodRequest = {
 
   fromPartial(object: DeepPartial<WriteMethodRequest>): WriteMethodRequest {
     const message = { ...baseWriteMethodRequest } as WriteMethodRequest;
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = '';
-    }
+    message.id = object.id ?? '';
     return message;
   },
 };
@@ -633,16 +621,8 @@ export const Entity = {
 
   fromPartial(object: DeepPartial<Entity>): Entity {
     const message = { ...baseEntity } as Entity;
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = '';
-    }
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.id = object.id ?? '';
+    message.name = object.name ?? '';
     return message;
   },
 };
diff --git a/integration/batching/batching.ts b/integration/batching/batching.ts
index 25a025910..abf7f953a 100644
--- a/integration/batching/batching.ts
+++ b/integration/batching/batching.ts
@@ -356,11 +356,7 @@ export const BatchMapQueryResponse_EntitiesEntry = {
 
   fromPartial(object: DeepPartial<BatchMapQueryResponse_EntitiesEntry>): BatchMapQueryResponse_EntitiesEntry {
     const message = { ...baseBatchMapQueryResponse_EntitiesEntry } as BatchMapQueryResponse_EntitiesEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = '';
-    }
+    message.key = object.key ?? '';
     if (object.value !== undefined && object.value !== null) {
       message.value = Entity.fromPartial(object.value);
     } else {
@@ -416,11 +412,7 @@ export const GetOnlyMethodRequest = {
 
   fromPartial(object: DeepPartial<GetOnlyMethodRequest>): GetOnlyMethodRequest {
     const message = { ...baseGetOnlyMethodRequest } as GetOnlyMethodRequest;
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = '';
-    }
+    message.id = object.id ?? '';
     return message;
   },
 };
@@ -526,11 +518,7 @@ export const WriteMethodRequest = {
 
   fromPartial(object: DeepPartial<WriteMethodRequest>): WriteMethodRequest {
     const message = { ...baseWriteMethodRequest } as WriteMethodRequest;
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = '';
-    }
+    message.id = object.id ?? '';
     return message;
   },
 };
@@ -631,16 +619,8 @@ export const Entity = {
 
   fromPartial(object: DeepPartial<Entity>): Entity {
     const message = { ...baseEntity } as Entity;
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = '';
-    }
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.id = object.id ?? '';
+    message.name = object.name ?? '';
     return message;
   },
 };
diff --git a/integration/bytes-as-base64/message.ts b/integration/bytes-as-base64/message.ts
index 35b95de65..6b5ebc662 100644
--- a/integration/bytes-as-base64/message.ts
+++ b/integration/bytes-as-base64/message.ts
@@ -29,11 +29,7 @@ export const Message = {
 
   fromPartial(object: DeepPartial<Message>): Message {
     const message = { ...baseMessage } as Message;
-    if (object.data !== undefined && object.data !== null) {
-      message.data = object.data;
-    } else {
-      message.data = new Uint8Array();
-    }
+    message.data = object.data ?? new Uint8Array();
     return message;
   },
 };
diff --git a/integration/bytes-node/point.ts b/integration/bytes-node/point.ts
index 51371174c..1a37383ba 100644
--- a/integration/bytes-node/point.ts
+++ b/integration/bytes-node/point.ts
@@ -55,11 +55,7 @@ export const Point = {
 
   fromPartial(object: DeepPartial<Point>): Point {
     const message = { ...basePoint } as Point;
-    if (object.data !== undefined && object.data !== null) {
-      message.data = object.data;
-    } else {
-      message.data = Buffer.alloc(0);
-    }
+    message.data = object.data ?? Buffer.alloc(0);
     return message;
   },
 };
diff --git a/integration/const-enum/const-enum.ts b/integration/const-enum/const-enum.ts
index 1d6f70569..2b59e47d5 100644
--- a/integration/const-enum/const-enum.ts
+++ b/integration/const-enum/const-enum.ts
@@ -113,11 +113,7 @@ export const DividerData = {
 
   fromPartial(object: DeepPartial<DividerData>): DividerData {
     const message = { ...baseDividerData } as DividerData;
-    if (object.type !== undefined && object.type !== null) {
-      message.type = object.type;
-    } else {
-      message.type = DividerData_DividerType.DOUBLE;
-    }
+    message.type = object.type ?? DividerData_DividerType.DOUBLE;
     return message;
   },
 };
diff --git a/integration/generic-service-definitions/simple.ts b/integration/generic-service-definitions/simple.ts
index 020613289..5c8c2a568 100644
--- a/integration/generic-service-definitions/simple.ts
+++ b/integration/generic-service-definitions/simple.ts
@@ -54,11 +54,7 @@ export const TestMessage = {
 
   fromPartial(object: DeepPartial<TestMessage>): TestMessage {
     const message = { ...baseTestMessage } as TestMessage;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = '';
-    }
+    message.value = object.value ?? '';
     return message;
   },
 };
diff --git a/integration/global-this/global-this.ts b/integration/global-this/global-this.ts
index 5fdc10435..8ce99ea98 100644
--- a/integration/global-this/global-this.ts
+++ b/integration/global-this/global-this.ts
@@ -58,11 +58,7 @@ export const Object = {
 
   fromPartial(object: DeepPartial<Object>): Object {
     const message = { ...baseObject } as Object;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     return message;
   },
 };
@@ -113,11 +109,7 @@ export const Error = {
 
   fromPartial(object: DeepPartial<Error>): Error {
     const message = { ...baseError } as Error;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     return message;
   },
 };
diff --git a/integration/grpc-js/google/protobuf/timestamp.ts b/integration/grpc-js/google/protobuf/timestamp.ts
index 52ea73adb..89f9a4fdb 100644
--- a/integration/grpc-js/google/protobuf/timestamp.ts
+++ b/integration/grpc-js/google/protobuf/timestamp.ts
@@ -162,16 +162,8 @@ export const Timestamp = {
 
   fromPartial(object: DeepPartial<Timestamp>): Timestamp {
     const message = { ...baseTimestamp } as Timestamp;
-    if (object.seconds !== undefined && object.seconds !== null) {
-      message.seconds = object.seconds;
-    } else {
-      message.seconds = 0;
-    }
-    if (object.nanos !== undefined && object.nanos !== null) {
-      message.nanos = object.nanos;
-    } else {
-      message.nanos = 0;
-    }
+    message.seconds = object.seconds ?? 0;
+    message.nanos = object.nanos ?? 0;
     return message;
   },
 };
diff --git a/integration/grpc-js/google/protobuf/wrappers.ts b/integration/grpc-js/google/protobuf/wrappers.ts
index 92da3e0a8..5f52d3fe7 100644
--- a/integration/grpc-js/google/protobuf/wrappers.ts
+++ b/integration/grpc-js/google/protobuf/wrappers.ts
@@ -140,11 +140,7 @@ export const DoubleValue = {
 
   fromPartial(object: DeepPartial<DoubleValue>): DoubleValue {
     const message = { ...baseDoubleValue } as DoubleValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -195,11 +191,7 @@ export const FloatValue = {
 
   fromPartial(object: DeepPartial<FloatValue>): FloatValue {
     const message = { ...baseFloatValue } as FloatValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -250,11 +242,7 @@ export const Int64Value = {
 
   fromPartial(object: DeepPartial<Int64Value>): Int64Value {
     const message = { ...baseInt64Value } as Int64Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -305,11 +293,7 @@ export const UInt64Value = {
 
   fromPartial(object: DeepPartial<UInt64Value>): UInt64Value {
     const message = { ...baseUInt64Value } as UInt64Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -360,11 +344,7 @@ export const Int32Value = {
 
   fromPartial(object: DeepPartial<Int32Value>): Int32Value {
     const message = { ...baseInt32Value } as Int32Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -415,11 +395,7 @@ export const UInt32Value = {
 
   fromPartial(object: DeepPartial<UInt32Value>): UInt32Value {
     const message = { ...baseUInt32Value } as UInt32Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -470,11 +446,7 @@ export const BoolValue = {
 
   fromPartial(object: DeepPartial<BoolValue>): BoolValue {
     const message = { ...baseBoolValue } as BoolValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = false;
-    }
+    message.value = object.value ?? false;
     return message;
   },
 };
@@ -525,11 +497,7 @@ export const StringValue = {
 
   fromPartial(object: DeepPartial<StringValue>): StringValue {
     const message = { ...baseStringValue } as StringValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = '';
-    }
+    message.value = object.value ?? '';
     return message;
   },
 };
@@ -581,11 +549,7 @@ export const BytesValue = {
 
   fromPartial(object: DeepPartial<BytesValue>): BytesValue {
     const message = { ...baseBytesValue } as BytesValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = new Uint8Array();
-    }
+    message.value = object.value ?? new Uint8Array();
     return message;
   },
 };
diff --git a/integration/grpc-js/simple.ts b/integration/grpc-js/simple.ts
index b8928314b..50138d1b7 100644
--- a/integration/grpc-js/simple.ts
+++ b/integration/grpc-js/simple.ts
@@ -85,11 +85,7 @@ export const TestMessage = {
 
   fromPartial(object: DeepPartial<TestMessage>): TestMessage {
     const message = { ...baseTestMessage } as TestMessage;
-    if (object.timestamp !== undefined && object.timestamp !== null) {
-      message.timestamp = object.timestamp;
-    } else {
-      message.timestamp = undefined;
-    }
+    message.timestamp = object.timestamp ?? undefined;
     return message;
   },
 };
diff --git a/integration/grpc-web-go-server/example.ts b/integration/grpc-web-go-server/example.ts
index 1135f99ba..cab052ced 100644
--- a/integration/grpc-web-go-server/example.ts
+++ b/integration/grpc-web-go-server/example.ts
@@ -149,16 +149,8 @@ export const DashFlash = {
 
   fromPartial(object: DeepPartial<DashFlash>): DashFlash {
     const message = { ...baseDashFlash } as DashFlash;
-    if (object.msg !== undefined && object.msg !== null) {
-      message.msg = object.msg;
-    } else {
-      message.msg = '';
-    }
-    if (object.type !== undefined && object.type !== null) {
-      message.type = object.type;
-    } else {
-      message.type = 0;
-    }
+    message.msg = object.msg ?? '';
+    message.type = object.type ?? 0;
     return message;
   },
 };
@@ -240,17 +232,13 @@ export const DashUserSettingsState = {
 
   fromPartial(object: DeepPartial<DashUserSettingsState>): DashUserSettingsState {
     const message = { ...baseDashUserSettingsState } as DashUserSettingsState;
-    message.flashes = [];
-    if (object.email !== undefined && object.email !== null) {
-      message.email = object.email;
-    } else {
-      message.email = '';
-    }
+    message.email = object.email ?? '';
     if (object.urls !== undefined && object.urls !== null) {
       message.urls = DashUserSettingsState_URLs.fromPartial(object.urls);
     } else {
       message.urls = undefined;
     }
+    message.flashes = [];
     if (object.flashes !== undefined && object.flashes !== null) {
       for (const e of object.flashes) {
         message.flashes.push(DashFlash.fromPartial(e));
@@ -318,16 +306,8 @@ export const DashUserSettingsState_URLs = {
 
   fromPartial(object: DeepPartial<DashUserSettingsState_URLs>): DashUserSettingsState_URLs {
     const message = { ...baseDashUserSettingsState_URLs } as DashUserSettingsState_URLs;
-    if (object.connectGoogle !== undefined && object.connectGoogle !== null) {
-      message.connectGoogle = object.connectGoogle;
-    } else {
-      message.connectGoogle = '';
-    }
-    if (object.connectGithub !== undefined && object.connectGithub !== null) {
-      message.connectGithub = object.connectGithub;
-    } else {
-      message.connectGithub = '';
-    }
+    message.connectGoogle = object.connectGoogle ?? '';
+    message.connectGithub = object.connectGithub ?? '';
     return message;
   },
 };
@@ -414,26 +394,10 @@ export const DashCred = {
 
   fromPartial(object: DeepPartial<DashCred>): DashCred {
     const message = { ...baseDashCred } as DashCred;
-    if (object.description !== undefined && object.description !== null) {
-      message.description = object.description;
-    } else {
-      message.description = '';
-    }
-    if (object.metadata !== undefined && object.metadata !== null) {
-      message.metadata = object.metadata;
-    } else {
-      message.metadata = '';
-    }
-    if (object.token !== undefined && object.token !== null) {
-      message.token = object.token;
-    } else {
-      message.token = '';
-    }
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = '';
-    }
+    message.description = object.description ?? '';
+    message.metadata = object.metadata ?? '';
+    message.token = object.token ?? '';
+    message.id = object.id ?? '';
     return message;
   },
 };
@@ -496,16 +460,8 @@ export const DashAPICredsCreateReq = {
 
   fromPartial(object: DeepPartial<DashAPICredsCreateReq>): DashAPICredsCreateReq {
     const message = { ...baseDashAPICredsCreateReq } as DashAPICredsCreateReq;
-    if (object.description !== undefined && object.description !== null) {
-      message.description = object.description;
-    } else {
-      message.description = '';
-    }
-    if (object.metadata !== undefined && object.metadata !== null) {
-      message.metadata = object.metadata;
-    } else {
-      message.metadata = '';
-    }
+    message.description = object.description ?? '';
+    message.metadata = object.metadata ?? '';
     return message;
   },
 };
@@ -592,26 +548,10 @@ export const DashAPICredsUpdateReq = {
 
   fromPartial(object: DeepPartial<DashAPICredsUpdateReq>): DashAPICredsUpdateReq {
     const message = { ...baseDashAPICredsUpdateReq } as DashAPICredsUpdateReq;
-    if (object.credSid !== undefined && object.credSid !== null) {
-      message.credSid = object.credSid;
-    } else {
-      message.credSid = '';
-    }
-    if (object.description !== undefined && object.description !== null) {
-      message.description = object.description;
-    } else {
-      message.description = '';
-    }
-    if (object.metadata !== undefined && object.metadata !== null) {
-      message.metadata = object.metadata;
-    } else {
-      message.metadata = '';
-    }
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = '';
-    }
+    message.credSid = object.credSid ?? '';
+    message.description = object.description ?? '';
+    message.metadata = object.metadata ?? '';
+    message.id = object.id ?? '';
     return message;
   },
 };
@@ -674,16 +614,8 @@ export const DashAPICredsDeleteReq = {
 
   fromPartial(object: DeepPartial<DashAPICredsDeleteReq>): DashAPICredsDeleteReq {
     const message = { ...baseDashAPICredsDeleteReq } as DashAPICredsDeleteReq;
-    if (object.credSid !== undefined && object.credSid !== null) {
-      message.credSid = object.credSid;
-    } else {
-      message.credSid = '';
-    }
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = '';
-    }
+    message.credSid = object.credSid ?? '';
+    message.id = object.id ?? '';
     return message;
   },
 };
diff --git a/integration/grpc-web-no-streaming-observable/example.ts b/integration/grpc-web-no-streaming-observable/example.ts
index d74f8dc15..a64377c43 100644
--- a/integration/grpc-web-no-streaming-observable/example.ts
+++ b/integration/grpc-web-no-streaming-observable/example.ts
@@ -128,16 +128,8 @@ export const DashFlash = {
 
   fromPartial(object: DeepPartial<DashFlash>): DashFlash {
     const message = { ...baseDashFlash } as DashFlash;
-    if (object.msg !== undefined && object.msg !== null) {
-      message.msg = object.msg;
-    } else {
-      message.msg = '';
-    }
-    if (object.type !== undefined && object.type !== null) {
-      message.type = object.type;
-    } else {
-      message.type = 0;
-    }
+    message.msg = object.msg ?? '';
+    message.type = object.type ?? 0;
     return message;
   },
 };
@@ -219,17 +211,13 @@ export const DashUserSettingsState = {
 
   fromPartial(object: DeepPartial<DashUserSettingsState>): DashUserSettingsState {
     const message = { ...baseDashUserSettingsState } as DashUserSettingsState;
-    message.flashes = [];
-    if (object.email !== undefined && object.email !== null) {
-      message.email = object.email;
-    } else {
-      message.email = '';
-    }
+    message.email = object.email ?? '';
     if (object.urls !== undefined && object.urls !== null) {
       message.urls = DashUserSettingsState_URLs.fromPartial(object.urls);
     } else {
       message.urls = undefined;
     }
+    message.flashes = [];
     if (object.flashes !== undefined && object.flashes !== null) {
       for (const e of object.flashes) {
         message.flashes.push(DashFlash.fromPartial(e));
@@ -297,16 +285,8 @@ export const DashUserSettingsState_URLs = {
 
   fromPartial(object: DeepPartial<DashUserSettingsState_URLs>): DashUserSettingsState_URLs {
     const message = { ...baseDashUserSettingsState_URLs } as DashUserSettingsState_URLs;
-    if (object.connectGoogle !== undefined && object.connectGoogle !== null) {
-      message.connectGoogle = object.connectGoogle;
-    } else {
-      message.connectGoogle = '';
-    }
-    if (object.connectGithub !== undefined && object.connectGithub !== null) {
-      message.connectGithub = object.connectGithub;
-    } else {
-      message.connectGithub = '';
-    }
+    message.connectGoogle = object.connectGoogle ?? '';
+    message.connectGithub = object.connectGithub ?? '';
     return message;
   },
 };
diff --git a/integration/grpc-web-no-streaming/example.ts b/integration/grpc-web-no-streaming/example.ts
index 3c307e85c..24a1d88a9 100644
--- a/integration/grpc-web-no-streaming/example.ts
+++ b/integration/grpc-web-no-streaming/example.ts
@@ -126,16 +126,8 @@ export const DashFlash = {
 
   fromPartial(object: DeepPartial<DashFlash>): DashFlash {
     const message = { ...baseDashFlash } as DashFlash;
-    if (object.msg !== undefined && object.msg !== null) {
-      message.msg = object.msg;
-    } else {
-      message.msg = '';
-    }
-    if (object.type !== undefined && object.type !== null) {
-      message.type = object.type;
-    } else {
-      message.type = 0;
-    }
+    message.msg = object.msg ?? '';
+    message.type = object.type ?? 0;
     return message;
   },
 };
@@ -217,17 +209,13 @@ export const DashUserSettingsState = {
 
   fromPartial(object: DeepPartial<DashUserSettingsState>): DashUserSettingsState {
     const message = { ...baseDashUserSettingsState } as DashUserSettingsState;
-    message.flashes = [];
-    if (object.email !== undefined && object.email !== null) {
-      message.email = object.email;
-    } else {
-      message.email = '';
-    }
+    message.email = object.email ?? '';
     if (object.urls !== undefined && object.urls !== null) {
       message.urls = DashUserSettingsState_URLs.fromPartial(object.urls);
     } else {
       message.urls = undefined;
     }
+    message.flashes = [];
     if (object.flashes !== undefined && object.flashes !== null) {
       for (const e of object.flashes) {
         message.flashes.push(DashFlash.fromPartial(e));
@@ -295,16 +283,8 @@ export const DashUserSettingsState_URLs = {
 
   fromPartial(object: DeepPartial<DashUserSettingsState_URLs>): DashUserSettingsState_URLs {
     const message = { ...baseDashUserSettingsState_URLs } as DashUserSettingsState_URLs;
-    if (object.connectGoogle !== undefined && object.connectGoogle !== null) {
-      message.connectGoogle = object.connectGoogle;
-    } else {
-      message.connectGoogle = '';
-    }
-    if (object.connectGithub !== undefined && object.connectGithub !== null) {
-      message.connectGithub = object.connectGithub;
-    } else {
-      message.connectGithub = '';
-    }
+    message.connectGoogle = object.connectGoogle ?? '';
+    message.connectGithub = object.connectGithub ?? '';
     return message;
   },
 };
diff --git a/integration/grpc-web/example.ts b/integration/grpc-web/example.ts
index 2c33dc068..90607b0ff 100644
--- a/integration/grpc-web/example.ts
+++ b/integration/grpc-web/example.ts
@@ -152,16 +152,8 @@ export const DashFlash = {
 
   fromPartial(object: DeepPartial<DashFlash>): DashFlash {
     const message = { ...baseDashFlash } as DashFlash;
-    if (object.msg !== undefined && object.msg !== null) {
-      message.msg = object.msg;
-    } else {
-      message.msg = '';
-    }
-    if (object.type !== undefined && object.type !== null) {
-      message.type = object.type;
-    } else {
-      message.type = 0;
-    }
+    message.msg = object.msg ?? '';
+    message.type = object.type ?? 0;
     return message;
   },
 };
@@ -243,17 +235,13 @@ export const DashUserSettingsState = {
 
   fromPartial(object: DeepPartial<DashUserSettingsState>): DashUserSettingsState {
     const message = { ...baseDashUserSettingsState } as DashUserSettingsState;
-    message.flashes = [];
-    if (object.email !== undefined && object.email !== null) {
-      message.email = object.email;
-    } else {
-      message.email = '';
-    }
+    message.email = object.email ?? '';
     if (object.urls !== undefined && object.urls !== null) {
       message.urls = DashUserSettingsState_URLs.fromPartial(object.urls);
     } else {
       message.urls = undefined;
     }
+    message.flashes = [];
     if (object.flashes !== undefined && object.flashes !== null) {
       for (const e of object.flashes) {
         message.flashes.push(DashFlash.fromPartial(e));
@@ -321,16 +309,8 @@ export const DashUserSettingsState_URLs = {
 
   fromPartial(object: DeepPartial<DashUserSettingsState_URLs>): DashUserSettingsState_URLs {
     const message = { ...baseDashUserSettingsState_URLs } as DashUserSettingsState_URLs;
-    if (object.connectGoogle !== undefined && object.connectGoogle !== null) {
-      message.connectGoogle = object.connectGoogle;
-    } else {
-      message.connectGoogle = '';
-    }
-    if (object.connectGithub !== undefined && object.connectGithub !== null) {
-      message.connectGithub = object.connectGithub;
-    } else {
-      message.connectGithub = '';
-    }
+    message.connectGoogle = object.connectGoogle ?? '';
+    message.connectGithub = object.connectGithub ?? '';
     return message;
   },
 };
@@ -417,26 +397,10 @@ export const DashCred = {
 
   fromPartial(object: DeepPartial<DashCred>): DashCred {
     const message = { ...baseDashCred } as DashCred;
-    if (object.description !== undefined && object.description !== null) {
-      message.description = object.description;
-    } else {
-      message.description = '';
-    }
-    if (object.metadata !== undefined && object.metadata !== null) {
-      message.metadata = object.metadata;
-    } else {
-      message.metadata = '';
-    }
-    if (object.token !== undefined && object.token !== null) {
-      message.token = object.token;
-    } else {
-      message.token = '';
-    }
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = '';
-    }
+    message.description = object.description ?? '';
+    message.metadata = object.metadata ?? '';
+    message.token = object.token ?? '';
+    message.id = object.id ?? '';
     return message;
   },
 };
@@ -499,16 +463,8 @@ export const DashAPICredsCreateReq = {
 
   fromPartial(object: DeepPartial<DashAPICredsCreateReq>): DashAPICredsCreateReq {
     const message = { ...baseDashAPICredsCreateReq } as DashAPICredsCreateReq;
-    if (object.description !== undefined && object.description !== null) {
-      message.description = object.description;
-    } else {
-      message.description = '';
-    }
-    if (object.metadata !== undefined && object.metadata !== null) {
-      message.metadata = object.metadata;
-    } else {
-      message.metadata = '';
-    }
+    message.description = object.description ?? '';
+    message.metadata = object.metadata ?? '';
     return message;
   },
 };
@@ -595,26 +551,10 @@ export const DashAPICredsUpdateReq = {
 
   fromPartial(object: DeepPartial<DashAPICredsUpdateReq>): DashAPICredsUpdateReq {
     const message = { ...baseDashAPICredsUpdateReq } as DashAPICredsUpdateReq;
-    if (object.credSid !== undefined && object.credSid !== null) {
-      message.credSid = object.credSid;
-    } else {
-      message.credSid = '';
-    }
-    if (object.description !== undefined && object.description !== null) {
-      message.description = object.description;
-    } else {
-      message.description = '';
-    }
-    if (object.metadata !== undefined && object.metadata !== null) {
-      message.metadata = object.metadata;
-    } else {
-      message.metadata = '';
-    }
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = '';
-    }
+    message.credSid = object.credSid ?? '';
+    message.description = object.description ?? '';
+    message.metadata = object.metadata ?? '';
+    message.id = object.id ?? '';
     return message;
   },
 };
@@ -677,16 +617,8 @@ export const DashAPICredsDeleteReq = {
 
   fromPartial(object: DeepPartial<DashAPICredsDeleteReq>): DashAPICredsDeleteReq {
     const message = { ...baseDashAPICredsDeleteReq } as DashAPICredsDeleteReq;
-    if (object.credSid !== undefined && object.credSid !== null) {
-      message.credSid = object.credSid;
-    } else {
-      message.credSid = '';
-    }
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = '';
-    }
+    message.credSid = object.credSid ?? '';
+    message.id = object.id ?? '';
     return message;
   },
 };
diff --git a/integration/lower-case-svc-methods/math.ts b/integration/lower-case-svc-methods/math.ts
index a82e96343..cf2627864 100644
--- a/integration/lower-case-svc-methods/math.ts
+++ b/integration/lower-case-svc-methods/math.ts
@@ -77,16 +77,8 @@ export const NumPair = {
 
   fromPartial(object: DeepPartial<NumPair>): NumPair {
     const message = { ...baseNumPair } as NumPair;
-    if (object.num1 !== undefined && object.num1 !== null) {
-      message.num1 = object.num1;
-    } else {
-      message.num1 = 0;
-    }
-    if (object.num2 !== undefined && object.num2 !== null) {
-      message.num2 = object.num2;
-    } else {
-      message.num2 = 0;
-    }
+    message.num1 = object.num1 ?? 0;
+    message.num2 = object.num2 ?? 0;
     return message;
   },
 };
@@ -137,11 +129,7 @@ export const NumSingle = {
 
   fromPartial(object: DeepPartial<NumSingle>): NumSingle {
     const message = { ...baseNumSingle } as NumSingle;
-    if (object.num !== undefined && object.num !== null) {
-      message.num = object.num;
-    } else {
-      message.num = 0;
-    }
+    message.num = object.num ?? 0;
     return message;
   },
 };
diff --git a/integration/no-proto-package/no-proto-package.ts b/integration/no-proto-package/no-proto-package.ts
index 4b5c6a19a..dd4dfd44e 100644
--- a/integration/no-proto-package/no-proto-package.ts
+++ b/integration/no-proto-package/no-proto-package.ts
@@ -57,11 +57,7 @@ export const User = {
 
   fromPartial(object: DeepPartial<User>): User {
     const message = { ...baseUser } as User;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     return message;
   },
 };
diff --git a/integration/oneof-properties/oneof.ts b/integration/oneof-properties/oneof.ts
index 135dffe81..8a1a2e31a 100644
--- a/integration/oneof-properties/oneof.ts
+++ b/integration/oneof-properties/oneof.ts
@@ -239,61 +239,21 @@ export const PleaseChoose = {
 
   fromPartial(object: DeepPartial<PleaseChoose>): PleaseChoose {
     const message = { ...basePleaseChoose } as PleaseChoose;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
-    if (object.aNumber !== undefined && object.aNumber !== null) {
-      message.aNumber = object.aNumber;
-    } else {
-      message.aNumber = undefined;
-    }
-    if (object.aString !== undefined && object.aString !== null) {
-      message.aString = object.aString;
-    } else {
-      message.aString = undefined;
-    }
+    message.name = object.name ?? '';
+    message.aNumber = object.aNumber ?? undefined;
+    message.aString = object.aString ?? undefined;
     if (object.aMessage !== undefined && object.aMessage !== null) {
       message.aMessage = PleaseChoose_Submessage.fromPartial(object.aMessage);
     } else {
       message.aMessage = undefined;
     }
-    if (object.aBool !== undefined && object.aBool !== null) {
-      message.aBool = object.aBool;
-    } else {
-      message.aBool = undefined;
-    }
-    if (object.bunchaBytes !== undefined && object.bunchaBytes !== null) {
-      message.bunchaBytes = object.bunchaBytes;
-    } else {
-      message.bunchaBytes = undefined;
-    }
-    if (object.anEnum !== undefined && object.anEnum !== null) {
-      message.anEnum = object.anEnum;
-    } else {
-      message.anEnum = undefined;
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = 0;
-    }
-    if (object.either !== undefined && object.either !== null) {
-      message.either = object.either;
-    } else {
-      message.either = undefined;
-    }
-    if (object.or !== undefined && object.or !== null) {
-      message.or = object.or;
-    } else {
-      message.or = undefined;
-    }
-    if (object.thirdOption !== undefined && object.thirdOption !== null) {
-      message.thirdOption = object.thirdOption;
-    } else {
-      message.thirdOption = undefined;
-    }
+    message.aBool = object.aBool ?? undefined;
+    message.bunchaBytes = object.bunchaBytes ?? undefined;
+    message.anEnum = object.anEnum ?? undefined;
+    message.age = object.age ?? 0;
+    message.either = object.either ?? undefined;
+    message.or = object.or ?? undefined;
+    message.thirdOption = object.thirdOption ?? undefined;
     return message;
   },
 };
@@ -344,11 +304,7 @@ export const PleaseChoose_Submessage = {
 
   fromPartial(object: DeepPartial<PleaseChoose_Submessage>): PleaseChoose_Submessage {
     const message = { ...basePleaseChoose_Submessage } as PleaseChoose_Submessage;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     return message;
   },
 };
diff --git a/integration/oneof-unions/oneof.ts b/integration/oneof-unions/oneof.ts
index 4f419f7fd..d0267744b 100644
--- a/integration/oneof-unions/oneof.ts
+++ b/integration/oneof-unions/oneof.ts
@@ -231,11 +231,7 @@ export const PleaseChoose = {
 
   fromPartial(object: DeepPartial<PleaseChoose>): PleaseChoose {
     const message = { ...basePleaseChoose } as PleaseChoose;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     if (object.choice?.$case === 'aNumber' && object.choice?.aNumber !== undefined && object.choice?.aNumber !== null) {
       message.choice = { $case: 'aNumber', aNumber: object.choice.aNumber };
     }
@@ -262,11 +258,7 @@ export const PleaseChoose = {
     if (object.choice?.$case === 'anEnum' && object.choice?.anEnum !== undefined && object.choice?.anEnum !== null) {
       message.choice = { $case: 'anEnum', anEnum: object.choice.anEnum };
     }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = 0;
-    }
+    message.age = object.age ?? 0;
     if (
       object.eitherOr?.$case === 'either' &&
       object.eitherOr?.either !== undefined &&
@@ -284,11 +276,7 @@ export const PleaseChoose = {
     ) {
       message.eitherOr = { $case: 'thirdOption', thirdOption: object.eitherOr.thirdOption };
     }
-    if (object.signature !== undefined && object.signature !== null) {
-      message.signature = object.signature;
-    } else {
-      message.signature = new Uint8Array();
-    }
+    message.signature = object.signature ?? new Uint8Array();
     return message;
   },
 };
@@ -337,11 +325,7 @@ export const PleaseChoose_Submessage = {
 
   fromPartial(object: DeepPartial<PleaseChoose_Submessage>): PleaseChoose_Submessage {
     const message = { ...basePleaseChoose_Submessage } as PleaseChoose_Submessage;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     return message;
   },
 };
@@ -400,16 +384,8 @@ export const SimpleButOptional = {
 
   fromPartial(object: DeepPartial<SimpleButOptional>): SimpleButOptional {
     const message = { ...baseSimpleButOptional } as SimpleButOptional;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = undefined;
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = undefined;
-    }
+    message.name = object.name ?? undefined;
+    message.age = object.age ?? undefined;
     return message;
   },
 };
diff --git a/integration/point/point.ts b/integration/point/point.ts
index 007ae47f2..af3c42bd5 100644
--- a/integration/point/point.ts
+++ b/integration/point/point.ts
@@ -72,16 +72,8 @@ export const Point = {
 
   fromPartial(object: DeepPartial<Point>): Point {
     const message = { ...basePoint } as Point;
-    if (object.lat !== undefined && object.lat !== null) {
-      message.lat = object.lat;
-    } else {
-      message.lat = 0;
-    }
-    if (object.lng !== undefined && object.lng !== null) {
-      message.lng = object.lng;
-    } else {
-      message.lng = 0;
-    }
+    message.lat = object.lat ?? 0;
+    message.lng = object.lng ?? 0;
     return message;
   },
 };
diff --git a/integration/return-observable/observable.ts b/integration/return-observable/observable.ts
index aa8e89d3b..1421c0efd 100644
--- a/integration/return-observable/observable.ts
+++ b/integration/return-observable/observable.ts
@@ -59,11 +59,7 @@ export const ProduceRequest = {
 
   fromPartial(object: DeepPartial<ProduceRequest>): ProduceRequest {
     const message = { ...baseProduceRequest } as ProduceRequest;
-    if (object.ingredients !== undefined && object.ingredients !== null) {
-      message.ingredients = object.ingredients;
-    } else {
-      message.ingredients = '';
-    }
+    message.ingredients = object.ingredients ?? '';
     return message;
   },
 };
@@ -114,11 +110,7 @@ export const ProduceReply = {
 
   fromPartial(object: DeepPartial<ProduceReply>): ProduceReply {
     const message = { ...baseProduceReply } as ProduceReply;
-    if (object.result !== undefined && object.result !== null) {
-      message.result = object.result;
-    } else {
-      message.result = '';
-    }
+    message.result = object.result ?? '';
     return message;
   },
 };
diff --git a/integration/simple-deprecated-fields/simple.ts b/integration/simple-deprecated-fields/simple.ts
index ec7ab7318..02cf008fc 100644
--- a/integration/simple-deprecated-fields/simple.ts
+++ b/integration/simple-deprecated-fields/simple.ts
@@ -126,31 +126,15 @@ export const Simple = {
 
   fromPartial(object: DeepPartial<Simple>): Simple {
     const message = { ...baseSimple } as Simple;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = 0;
-    }
+    message.name = object.name ?? '';
+    message.age = object.age ?? 0;
     if (object.child !== undefined && object.child !== null) {
       message.child = Child.fromPartial(object.child);
     } else {
       message.child = undefined;
     }
-    if (object.testField !== undefined && object.testField !== null) {
-      message.testField = object.testField;
-    } else {
-      message.testField = '';
-    }
-    if (object.testNotDeprecated !== undefined && object.testNotDeprecated !== null) {
-      message.testNotDeprecated = object.testNotDeprecated;
-    } else {
-      message.testNotDeprecated = '';
-    }
+    message.testField = object.testField ?? '';
+    message.testNotDeprecated = object.testNotDeprecated ?? '';
     return message;
   },
 };
@@ -201,11 +185,7 @@ export const Child = {
 
   fromPartial(object: DeepPartial<Child>): Child {
     const message = { ...baseChild } as Child;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     return message;
   },
 };
diff --git a/integration/simple-esmodule-interop/simple.ts b/integration/simple-esmodule-interop/simple.ts
index d8848a67f..893eb0d71 100644
--- a/integration/simple-esmodule-interop/simple.ts
+++ b/integration/simple-esmodule-interop/simple.ts
@@ -82,16 +82,8 @@ export const Simple = {
 
   fromPartial(object: DeepPartial<Simple>): Simple {
     const message = { ...baseSimple } as Simple;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = 0;
-    }
+    message.name = object.name ?? '';
+    message.age = object.age ?? 0;
     return message;
   },
 };
@@ -287,66 +279,18 @@ export const Numbers = {
 
   fromPartial(object: DeepPartial<Numbers>): Numbers {
     const message = { ...baseNumbers } as Numbers;
-    if (object.double !== undefined && object.double !== null) {
-      message.double = object.double;
-    } else {
-      message.double = 0;
-    }
-    if (object.float !== undefined && object.float !== null) {
-      message.float = object.float;
-    } else {
-      message.float = 0;
-    }
-    if (object.int32 !== undefined && object.int32 !== null) {
-      message.int32 = object.int32;
-    } else {
-      message.int32 = 0;
-    }
-    if (object.int64 !== undefined && object.int64 !== null) {
-      message.int64 = object.int64;
-    } else {
-      message.int64 = 0;
-    }
-    if (object.uint32 !== undefined && object.uint32 !== null) {
-      message.uint32 = object.uint32;
-    } else {
-      message.uint32 = 0;
-    }
-    if (object.uint64 !== undefined && object.uint64 !== null) {
-      message.uint64 = object.uint64;
-    } else {
-      message.uint64 = 0;
-    }
-    if (object.sint32 !== undefined && object.sint32 !== null) {
-      message.sint32 = object.sint32;
-    } else {
-      message.sint32 = 0;
-    }
-    if (object.sint64 !== undefined && object.sint64 !== null) {
-      message.sint64 = object.sint64;
-    } else {
-      message.sint64 = 0;
-    }
-    if (object.fixed32 !== undefined && object.fixed32 !== null) {
-      message.fixed32 = object.fixed32;
-    } else {
-      message.fixed32 = 0;
-    }
-    if (object.fixed64 !== undefined && object.fixed64 !== null) {
-      message.fixed64 = object.fixed64;
-    } else {
-      message.fixed64 = 0;
-    }
-    if (object.sfixed32 !== undefined && object.sfixed32 !== null) {
-      message.sfixed32 = object.sfixed32;
-    } else {
-      message.sfixed32 = 0;
-    }
-    if (object.sfixed64 !== undefined && object.sfixed64 !== null) {
-      message.sfixed64 = object.sfixed64;
-    } else {
-      message.sfixed64 = 0;
-    }
+    message.double = object.double ?? 0;
+    message.float = object.float ?? 0;
+    message.int32 = object.int32 ?? 0;
+    message.int64 = object.int64 ?? 0;
+    message.uint32 = object.uint32 ?? 0;
+    message.uint64 = object.uint64 ?? 0;
+    message.sint32 = object.sint32 ?? 0;
+    message.sint64 = object.sint64 ?? 0;
+    message.fixed32 = object.fixed32 ?? 0;
+    message.fixed64 = object.fixed64 ?? 0;
+    message.sfixed32 = object.sfixed32 ?? 0;
+    message.sfixed64 = object.sfixed64 ?? 0;
     return message;
   },
 };
diff --git a/integration/simple-long-string/google/protobuf/timestamp.ts b/integration/simple-long-string/google/protobuf/timestamp.ts
index 8795fb381..f9bcc2476 100644
--- a/integration/simple-long-string/google/protobuf/timestamp.ts
+++ b/integration/simple-long-string/google/protobuf/timestamp.ts
@@ -162,16 +162,8 @@ export const Timestamp = {
 
   fromPartial(object: DeepPartial<Timestamp>): Timestamp {
     const message = { ...baseTimestamp } as Timestamp;
-    if (object.seconds !== undefined && object.seconds !== null) {
-      message.seconds = object.seconds;
-    } else {
-      message.seconds = '0';
-    }
-    if (object.nanos !== undefined && object.nanos !== null) {
-      message.nanos = object.nanos;
-    } else {
-      message.nanos = 0;
-    }
+    message.seconds = object.seconds ?? '0';
+    message.nanos = object.nanos ?? 0;
     return message;
   },
 };
diff --git a/integration/simple-long-string/google/protobuf/wrappers.ts b/integration/simple-long-string/google/protobuf/wrappers.ts
index 95bb5ea22..9ca672531 100644
--- a/integration/simple-long-string/google/protobuf/wrappers.ts
+++ b/integration/simple-long-string/google/protobuf/wrappers.ts
@@ -140,11 +140,7 @@ export const DoubleValue = {
 
   fromPartial(object: DeepPartial<DoubleValue>): DoubleValue {
     const message = { ...baseDoubleValue } as DoubleValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -195,11 +191,7 @@ export const FloatValue = {
 
   fromPartial(object: DeepPartial<FloatValue>): FloatValue {
     const message = { ...baseFloatValue } as FloatValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -250,11 +242,7 @@ export const Int64Value = {
 
   fromPartial(object: DeepPartial<Int64Value>): Int64Value {
     const message = { ...baseInt64Value } as Int64Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = '0';
-    }
+    message.value = object.value ?? '0';
     return message;
   },
 };
@@ -305,11 +293,7 @@ export const UInt64Value = {
 
   fromPartial(object: DeepPartial<UInt64Value>): UInt64Value {
     const message = { ...baseUInt64Value } as UInt64Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = '0';
-    }
+    message.value = object.value ?? '0';
     return message;
   },
 };
@@ -360,11 +344,7 @@ export const Int32Value = {
 
   fromPartial(object: DeepPartial<Int32Value>): Int32Value {
     const message = { ...baseInt32Value } as Int32Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -415,11 +395,7 @@ export const UInt32Value = {
 
   fromPartial(object: DeepPartial<UInt32Value>): UInt32Value {
     const message = { ...baseUInt32Value } as UInt32Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -470,11 +446,7 @@ export const BoolValue = {
 
   fromPartial(object: DeepPartial<BoolValue>): BoolValue {
     const message = { ...baseBoolValue } as BoolValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = false;
-    }
+    message.value = object.value ?? false;
     return message;
   },
 };
@@ -525,11 +497,7 @@ export const StringValue = {
 
   fromPartial(object: DeepPartial<StringValue>): StringValue {
     const message = { ...baseStringValue } as StringValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = '';
-    }
+    message.value = object.value ?? '';
     return message;
   },
 };
@@ -581,11 +549,7 @@ export const BytesValue = {
 
   fromPartial(object: DeepPartial<BytesValue>): BytesValue {
     const message = { ...baseBytesValue } as BytesValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = new Uint8Array();
-    }
+    message.value = object.value ?? new Uint8Array();
     return message;
   },
 };
diff --git a/integration/simple-long-string/simple.ts b/integration/simple-long-string/simple.ts
index 4ced72ccd..e36bf4842 100644
--- a/integration/simple-long-string/simple.ts
+++ b/integration/simple-long-string/simple.ts
@@ -238,76 +238,20 @@ export const Numbers = {
 
   fromPartial(object: DeepPartial<Numbers>): Numbers {
     const message = { ...baseNumbers } as Numbers;
-    if (object.double !== undefined && object.double !== null) {
-      message.double = object.double;
-    } else {
-      message.double = 0;
-    }
-    if (object.float !== undefined && object.float !== null) {
-      message.float = object.float;
-    } else {
-      message.float = 0;
-    }
-    if (object.int32 !== undefined && object.int32 !== null) {
-      message.int32 = object.int32;
-    } else {
-      message.int32 = 0;
-    }
-    if (object.int64 !== undefined && object.int64 !== null) {
-      message.int64 = object.int64;
-    } else {
-      message.int64 = '0';
-    }
-    if (object.uint32 !== undefined && object.uint32 !== null) {
-      message.uint32 = object.uint32;
-    } else {
-      message.uint32 = 0;
-    }
-    if (object.uint64 !== undefined && object.uint64 !== null) {
-      message.uint64 = object.uint64;
-    } else {
-      message.uint64 = '0';
-    }
-    if (object.sint32 !== undefined && object.sint32 !== null) {
-      message.sint32 = object.sint32;
-    } else {
-      message.sint32 = 0;
-    }
-    if (object.sint64 !== undefined && object.sint64 !== null) {
-      message.sint64 = object.sint64;
-    } else {
-      message.sint64 = '0';
-    }
-    if (object.fixed32 !== undefined && object.fixed32 !== null) {
-      message.fixed32 = object.fixed32;
-    } else {
-      message.fixed32 = 0;
-    }
-    if (object.fixed64 !== undefined && object.fixed64 !== null) {
-      message.fixed64 = object.fixed64;
-    } else {
-      message.fixed64 = '0';
-    }
-    if (object.sfixed32 !== undefined && object.sfixed32 !== null) {
-      message.sfixed32 = object.sfixed32;
-    } else {
-      message.sfixed32 = 0;
-    }
-    if (object.sfixed64 !== undefined && object.sfixed64 !== null) {
-      message.sfixed64 = object.sfixed64;
-    } else {
-      message.sfixed64 = '0';
-    }
-    if (object.guint64 !== undefined && object.guint64 !== null) {
-      message.guint64 = object.guint64;
-    } else {
-      message.guint64 = undefined;
-    }
-    if (object.timestamp !== undefined && object.timestamp !== null) {
-      message.timestamp = object.timestamp;
-    } else {
-      message.timestamp = undefined;
-    }
+    message.double = object.double ?? 0;
+    message.float = object.float ?? 0;
+    message.int32 = object.int32 ?? 0;
+    message.int64 = object.int64 ?? '0';
+    message.uint32 = object.uint32 ?? 0;
+    message.uint64 = object.uint64 ?? '0';
+    message.sint32 = object.sint32 ?? 0;
+    message.sint64 = object.sint64 ?? '0';
+    message.fixed32 = object.fixed32 ?? 0;
+    message.fixed64 = object.fixed64 ?? '0';
+    message.sfixed32 = object.sfixed32 ?? 0;
+    message.sfixed64 = object.sfixed64 ?? '0';
+    message.guint64 = object.guint64 ?? undefined;
+    message.timestamp = object.timestamp ?? undefined;
     return message;
   },
 };
diff --git a/integration/simple-long/google/protobuf/wrappers.ts b/integration/simple-long/google/protobuf/wrappers.ts
index b6ec1513e..f63d5b340 100644
--- a/integration/simple-long/google/protobuf/wrappers.ts
+++ b/integration/simple-long/google/protobuf/wrappers.ts
@@ -140,11 +140,7 @@ export const DoubleValue = {
 
   fromPartial(object: DeepPartial<DoubleValue>): DoubleValue {
     const message = { ...baseDoubleValue } as DoubleValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -195,11 +191,7 @@ export const FloatValue = {
 
   fromPartial(object: DeepPartial<FloatValue>): FloatValue {
     const message = { ...baseFloatValue } as FloatValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -360,11 +352,7 @@ export const Int32Value = {
 
   fromPartial(object: DeepPartial<Int32Value>): Int32Value {
     const message = { ...baseInt32Value } as Int32Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -415,11 +403,7 @@ export const UInt32Value = {
 
   fromPartial(object: DeepPartial<UInt32Value>): UInt32Value {
     const message = { ...baseUInt32Value } as UInt32Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -470,11 +454,7 @@ export const BoolValue = {
 
   fromPartial(object: DeepPartial<BoolValue>): BoolValue {
     const message = { ...baseBoolValue } as BoolValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = false;
-    }
+    message.value = object.value ?? false;
     return message;
   },
 };
@@ -525,11 +505,7 @@ export const StringValue = {
 
   fromPartial(object: DeepPartial<StringValue>): StringValue {
     const message = { ...baseStringValue } as StringValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = '';
-    }
+    message.value = object.value ?? '';
     return message;
   },
 };
@@ -581,11 +557,7 @@ export const BytesValue = {
 
   fromPartial(object: DeepPartial<BytesValue>): BytesValue {
     const message = { ...baseBytesValue } as BytesValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = new Uint8Array();
-    }
+    message.value = object.value ?? new Uint8Array();
     return message;
   },
 };
diff --git a/integration/simple-long/simple.ts b/integration/simple-long/simple.ts
index 6e0a8392b..56d902e5e 100644
--- a/integration/simple-long/simple.ts
+++ b/integration/simple-long/simple.ts
@@ -164,33 +164,21 @@ export const SimpleWithWrappers = {
 
   fromPartial(object: DeepPartial<SimpleWithWrappers>): SimpleWithWrappers {
     const message = { ...baseSimpleWithWrappers } as SimpleWithWrappers;
-    message.coins = [];
-    message.snacks = [];
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = undefined;
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = undefined;
-    }
-    if (object.enabled !== undefined && object.enabled !== null) {
-      message.enabled = object.enabled;
-    } else {
-      message.enabled = undefined;
-    }
+    message.name = object.name ?? undefined;
+    message.age = object.age ?? undefined;
+    message.enabled = object.enabled ?? undefined;
     if (object.bananas !== undefined && object.bananas !== null) {
       message.bananas = object.bananas as Long | undefined;
     } else {
       message.bananas = undefined;
     }
+    message.coins = [];
     if (object.coins !== undefined && object.coins !== null) {
       for (const e of object.coins) {
         message.coins.push(e);
       }
     }
+    message.snacks = [];
     if (object.snacks !== undefined && object.snacks !== null) {
       for (const e of object.snacks) {
         message.snacks.push(e);
@@ -279,7 +267,6 @@ export const SimpleWithMap = {
   fromPartial(object: DeepPartial<SimpleWithMap>): SimpleWithMap {
     const message = { ...baseSimpleWithMap } as SimpleWithMap;
     message.nameLookup = {};
-    message.intLookup = {};
     if (object.nameLookup !== undefined && object.nameLookup !== null) {
       Object.entries(object.nameLookup).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -287,6 +274,7 @@ export const SimpleWithMap = {
         }
       });
     }
+    message.intLookup = {};
     if (object.intLookup !== undefined && object.intLookup !== null) {
       Object.entries(object.intLookup).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -356,16 +344,8 @@ export const SimpleWithMap_NameLookupEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_NameLookupEntry>): SimpleWithMap_NameLookupEntry {
     const message = { ...baseSimpleWithMap_NameLookupEntry } as SimpleWithMap_NameLookupEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = '';
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = '';
-    }
+    message.key = object.key ?? '';
+    message.value = object.value ?? '';
     return message;
   },
 };
@@ -428,16 +408,8 @@ export const SimpleWithMap_IntLookupEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_IntLookupEntry>): SimpleWithMap_IntLookupEntry {
     const message = { ...baseSimpleWithMap_IntLookupEntry } as SimpleWithMap_IntLookupEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = 0;
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.key = object.key ?? 0;
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -661,67 +633,39 @@ export const Numbers = {
 
   fromPartial(object: DeepPartial<Numbers>): Numbers {
     const message = { ...baseNumbers } as Numbers;
-    message.manyUint64 = [];
-    if (object.double !== undefined && object.double !== null) {
-      message.double = object.double;
-    } else {
-      message.double = 0;
-    }
-    if (object.float !== undefined && object.float !== null) {
-      message.float = object.float;
-    } else {
-      message.float = 0;
-    }
-    if (object.int32 !== undefined && object.int32 !== null) {
-      message.int32 = object.int32;
-    } else {
-      message.int32 = 0;
-    }
+    message.double = object.double ?? 0;
+    message.float = object.float ?? 0;
+    message.int32 = object.int32 ?? 0;
     if (object.int64 !== undefined && object.int64 !== null) {
       message.int64 = object.int64 as Long;
     } else {
       message.int64 = Long.ZERO;
     }
-    if (object.uint32 !== undefined && object.uint32 !== null) {
-      message.uint32 = object.uint32;
-    } else {
-      message.uint32 = 0;
-    }
+    message.uint32 = object.uint32 ?? 0;
     if (object.uint64 !== undefined && object.uint64 !== null) {
       message.uint64 = object.uint64 as Long;
     } else {
       message.uint64 = Long.UZERO;
     }
-    if (object.sint32 !== undefined && object.sint32 !== null) {
-      message.sint32 = object.sint32;
-    } else {
-      message.sint32 = 0;
-    }
+    message.sint32 = object.sint32 ?? 0;
     if (object.sint64 !== undefined && object.sint64 !== null) {
       message.sint64 = object.sint64 as Long;
     } else {
       message.sint64 = Long.ZERO;
     }
-    if (object.fixed32 !== undefined && object.fixed32 !== null) {
-      message.fixed32 = object.fixed32;
-    } else {
-      message.fixed32 = 0;
-    }
+    message.fixed32 = object.fixed32 ?? 0;
     if (object.fixed64 !== undefined && object.fixed64 !== null) {
       message.fixed64 = object.fixed64 as Long;
     } else {
       message.fixed64 = Long.UZERO;
     }
-    if (object.sfixed32 !== undefined && object.sfixed32 !== null) {
-      message.sfixed32 = object.sfixed32;
-    } else {
-      message.sfixed32 = 0;
-    }
+    message.sfixed32 = object.sfixed32 ?? 0;
     if (object.sfixed64 !== undefined && object.sfixed64 !== null) {
       message.sfixed64 = object.sfixed64 as Long;
     } else {
       message.sfixed64 = Long.ZERO;
     }
+    message.manyUint64 = [];
     if (object.manyUint64 !== undefined && object.manyUint64 !== null) {
       for (const e of object.manyUint64) {
         message.manyUint64.push(e);
diff --git a/integration/simple-optionals/google/protobuf/timestamp.ts b/integration/simple-optionals/google/protobuf/timestamp.ts
index 52ea73adb..89f9a4fdb 100644
--- a/integration/simple-optionals/google/protobuf/timestamp.ts
+++ b/integration/simple-optionals/google/protobuf/timestamp.ts
@@ -162,16 +162,8 @@ export const Timestamp = {
 
   fromPartial(object: DeepPartial<Timestamp>): Timestamp {
     const message = { ...baseTimestamp } as Timestamp;
-    if (object.seconds !== undefined && object.seconds !== null) {
-      message.seconds = object.seconds;
-    } else {
-      message.seconds = 0;
-    }
-    if (object.nanos !== undefined && object.nanos !== null) {
-      message.nanos = object.nanos;
-    } else {
-      message.nanos = 0;
-    }
+    message.seconds = object.seconds ?? 0;
+    message.nanos = object.nanos ?? 0;
     return message;
   },
 };
diff --git a/integration/simple-optionals/google/protobuf/wrappers.ts b/integration/simple-optionals/google/protobuf/wrappers.ts
index 92da3e0a8..5f52d3fe7 100644
--- a/integration/simple-optionals/google/protobuf/wrappers.ts
+++ b/integration/simple-optionals/google/protobuf/wrappers.ts
@@ -140,11 +140,7 @@ export const DoubleValue = {
 
   fromPartial(object: DeepPartial<DoubleValue>): DoubleValue {
     const message = { ...baseDoubleValue } as DoubleValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -195,11 +191,7 @@ export const FloatValue = {
 
   fromPartial(object: DeepPartial<FloatValue>): FloatValue {
     const message = { ...baseFloatValue } as FloatValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -250,11 +242,7 @@ export const Int64Value = {
 
   fromPartial(object: DeepPartial<Int64Value>): Int64Value {
     const message = { ...baseInt64Value } as Int64Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -305,11 +293,7 @@ export const UInt64Value = {
 
   fromPartial(object: DeepPartial<UInt64Value>): UInt64Value {
     const message = { ...baseUInt64Value } as UInt64Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -360,11 +344,7 @@ export const Int32Value = {
 
   fromPartial(object: DeepPartial<Int32Value>): Int32Value {
     const message = { ...baseInt32Value } as Int32Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -415,11 +395,7 @@ export const UInt32Value = {
 
   fromPartial(object: DeepPartial<UInt32Value>): UInt32Value {
     const message = { ...baseUInt32Value } as UInt32Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -470,11 +446,7 @@ export const BoolValue = {
 
   fromPartial(object: DeepPartial<BoolValue>): BoolValue {
     const message = { ...baseBoolValue } as BoolValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = false;
-    }
+    message.value = object.value ?? false;
     return message;
   },
 };
@@ -525,11 +497,7 @@ export const StringValue = {
 
   fromPartial(object: DeepPartial<StringValue>): StringValue {
     const message = { ...baseStringValue } as StringValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = '';
-    }
+    message.value = object.value ?? '';
     return message;
   },
 };
@@ -581,11 +549,7 @@ export const BytesValue = {
 
   fromPartial(object: DeepPartial<BytesValue>): BytesValue {
     const message = { ...baseBytesValue } as BytesValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = new Uint8Array();
-    }
+    message.value = object.value ?? new Uint8Array();
     return message;
   },
 };
diff --git a/integration/simple-optionals/import_dir/thing.ts b/integration/simple-optionals/import_dir/thing.ts
index 8acd814c2..bc254a2a7 100644
--- a/integration/simple-optionals/import_dir/thing.ts
+++ b/integration/simple-optionals/import_dir/thing.ts
@@ -55,11 +55,7 @@ export const ImportedThing = {
 
   fromPartial(object: DeepPartial<ImportedThing>): ImportedThing {
     const message = { ...baseImportedThing } as ImportedThing;
-    if (object.createdAt !== undefined && object.createdAt !== null) {
-      message.createdAt = object.createdAt;
-    } else {
-      message.createdAt = undefined;
-    }
+    message.createdAt = object.createdAt ?? undefined;
     return message;
   },
 };
diff --git a/integration/simple-optionals/simple.ts b/integration/simple-optionals/simple.ts
index edb7bea62..e1f10ef75 100644
--- a/integration/simple-optionals/simple.ts
+++ b/integration/simple-optionals/simple.ts
@@ -431,50 +431,34 @@ export const Simple = {
 
   fromPartial(object: DeepPartial<Simple>): Simple {
     const message = { ...baseSimple } as Simple;
-    message.grandChildren = [];
-    message.coins = [];
-    message.snacks = [];
-    message.oldStates = [];
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = 0;
-    }
-    if (object.createdAt !== undefined && object.createdAt !== null) {
-      message.createdAt = object.createdAt;
-    } else {
-      message.createdAt = undefined;
-    }
+    message.name = object.name ?? '';
+    message.age = object.age ?? 0;
+    message.createdAt = object.createdAt ?? undefined;
     if (object.child !== undefined && object.child !== null) {
       message.child = Child.fromPartial(object.child);
     } else {
       message.child = undefined;
     }
-    if (object.state !== undefined && object.state !== null) {
-      message.state = object.state;
-    } else {
-      message.state = 0;
-    }
+    message.state = object.state ?? 0;
+    message.grandChildren = [];
     if (object.grandChildren !== undefined && object.grandChildren !== null) {
       for (const e of object.grandChildren) {
         message.grandChildren.push(Child.fromPartial(e));
       }
     }
+    message.coins = [];
     if (object.coins !== undefined && object.coins !== null) {
       for (const e of object.coins) {
         message.coins.push(e);
       }
     }
+    message.snacks = [];
     if (object.snacks !== undefined && object.snacks !== null) {
       for (const e of object.snacks) {
         message.snacks.push(e);
       }
     }
+    message.oldStates = [];
     if (object.oldStates !== undefined && object.oldStates !== null) {
       for (const e of object.oldStates) {
         message.oldStates.push(e);
@@ -547,16 +531,8 @@ export const Child = {
 
   fromPartial(object: DeepPartial<Child>): Child {
     const message = { ...baseChild } as Child;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
-    if (object.type !== undefined && object.type !== null) {
-      message.type = object.type;
-    } else {
-      message.type = 0;
-    }
+    message.name = object.name ?? '';
+    message.type = object.type ?? 0;
     return message;
   },
 };
@@ -632,21 +608,13 @@ export const Nested = {
 
   fromPartial(object: DeepPartial<Nested>): Nested {
     const message = { ...baseNested } as Nested;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     if (object.message !== undefined && object.message !== null) {
       message.message = Nested_InnerMessage.fromPartial(object.message);
     } else {
       message.message = undefined;
     }
-    if (object.state !== undefined && object.state !== null) {
-      message.state = object.state;
-    } else {
-      message.state = 0;
-    }
+    message.state = object.state ?? 0;
     return message;
   },
 };
@@ -710,11 +678,7 @@ export const Nested_InnerMessage = {
 
   fromPartial(object: DeepPartial<Nested_InnerMessage>): Nested_InnerMessage {
     const message = { ...baseNested_InnerMessage } as Nested_InnerMessage;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     if (object.deep !== undefined && object.deep !== null) {
       message.deep = Nested_InnerMessage_DeepMessage.fromPartial(object.deep);
     } else {
@@ -770,11 +734,7 @@ export const Nested_InnerMessage_DeepMessage = {
 
   fromPartial(object: DeepPartial<Nested_InnerMessage_DeepMessage>): Nested_InnerMessage_DeepMessage {
     const message = { ...baseNested_InnerMessage_DeepMessage } as Nested_InnerMessage_DeepMessage;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     return message;
   },
 };
@@ -837,16 +797,8 @@ export const OneOfMessage = {
 
   fromPartial(object: DeepPartial<OneOfMessage>): OneOfMessage {
     const message = { ...baseOneOfMessage } as OneOfMessage;
-    if (object.first !== undefined && object.first !== null) {
-      message.first = object.first;
-    } else {
-      message.first = undefined;
-    }
-    if (object.last !== undefined && object.last !== null) {
-      message.last = object.last;
-    } else {
-      message.last = undefined;
-    }
+    message.first = object.first ?? undefined;
+    message.last = object.last ?? undefined;
     return message;
   },
 };
@@ -957,28 +909,16 @@ export const SimpleWithWrappers = {
 
   fromPartial(object: DeepPartial<SimpleWithWrappers>): SimpleWithWrappers {
     const message = { ...baseSimpleWithWrappers } as SimpleWithWrappers;
+    message.name = object.name ?? undefined;
+    message.age = object.age ?? undefined;
+    message.enabled = object.enabled ?? undefined;
     message.coins = [];
-    message.snacks = [];
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = undefined;
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = undefined;
-    }
-    if (object.enabled !== undefined && object.enabled !== null) {
-      message.enabled = object.enabled;
-    } else {
-      message.enabled = undefined;
-    }
     if (object.coins !== undefined && object.coins !== null) {
       for (const e of object.coins) {
         message.coins.push(e);
       }
     }
+    message.snacks = [];
     if (object.snacks !== undefined && object.snacks !== null) {
       for (const e of object.snacks) {
         message.snacks.push(e);
@@ -1034,11 +974,7 @@ export const Entity = {
 
   fromPartial(object: DeepPartial<Entity>): Entity {
     const message = { ...baseEntity } as Entity;
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = 0;
-    }
+    message.id = object.id ?? 0;
     return message;
   },
 };
@@ -1144,8 +1080,6 @@ export const SimpleWithMap = {
   fromPartial(object: DeepPartial<SimpleWithMap>): SimpleWithMap {
     const message = { ...baseSimpleWithMap } as SimpleWithMap;
     message.entitiesById = {};
-    message.nameLookup = {};
-    message.intLookup = {};
     if (object.entitiesById !== undefined && object.entitiesById !== null) {
       Object.entries(object.entitiesById).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -1153,6 +1087,7 @@ export const SimpleWithMap = {
         }
       });
     }
+    message.nameLookup = {};
     if (object.nameLookup !== undefined && object.nameLookup !== null) {
       Object.entries(object.nameLookup).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -1160,6 +1095,7 @@ export const SimpleWithMap = {
         }
       });
     }
+    message.intLookup = {};
     if (object.intLookup !== undefined && object.intLookup !== null) {
       Object.entries(object.intLookup).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -1229,11 +1165,7 @@ export const SimpleWithMap_EntitiesByIdEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_EntitiesByIdEntry>): SimpleWithMap_EntitiesByIdEntry {
     const message = { ...baseSimpleWithMap_EntitiesByIdEntry } as SimpleWithMap_EntitiesByIdEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = 0;
-    }
+    message.key = object.key ?? 0;
     if (object.value !== undefined && object.value !== null) {
       message.value = Entity.fromPartial(object.value);
     } else {
@@ -1301,16 +1233,8 @@ export const SimpleWithMap_NameLookupEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_NameLookupEntry>): SimpleWithMap_NameLookupEntry {
     const message = { ...baseSimpleWithMap_NameLookupEntry } as SimpleWithMap_NameLookupEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = '';
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = '';
-    }
+    message.key = object.key ?? '';
+    message.value = object.value ?? '';
     return message;
   },
 };
@@ -1373,16 +1297,8 @@ export const SimpleWithMap_IntLookupEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_IntLookupEntry>): SimpleWithMap_IntLookupEntry {
     const message = { ...baseSimpleWithMap_IntLookupEntry } as SimpleWithMap_IntLookupEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = 0;
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.key = object.key ?? 0;
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -1513,11 +1429,7 @@ export const SimpleWithSnakeCaseMap_EntitiesByIdEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithSnakeCaseMap_EntitiesByIdEntry>): SimpleWithSnakeCaseMap_EntitiesByIdEntry {
     const message = { ...baseSimpleWithSnakeCaseMap_EntitiesByIdEntry } as SimpleWithSnakeCaseMap_EntitiesByIdEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = 0;
-    }
+    message.key = object.key ?? 0;
     if (object.value !== undefined && object.value !== null) {
       message.value = Entity.fromPartial(object.value);
     } else {
@@ -1573,11 +1485,7 @@ export const PingRequest = {
 
   fromPartial(object: DeepPartial<PingRequest>): PingRequest {
     const message = { ...basePingRequest } as PingRequest;
-    if (object.input !== undefined && object.input !== null) {
-      message.input = object.input;
-    } else {
-      message.input = '';
-    }
+    message.input = object.input ?? '';
     return message;
   },
 };
@@ -1628,11 +1536,7 @@ export const PingResponse = {
 
   fromPartial(object: DeepPartial<PingResponse>): PingResponse {
     const message = { ...basePingResponse } as PingResponse;
-    if (object.output !== undefined && object.output !== null) {
-      message.output = object.output;
-    } else {
-      message.output = '';
-    }
+    message.output = object.output ?? '';
     return message;
   },
 };
@@ -1828,66 +1732,18 @@ export const Numbers = {
 
   fromPartial(object: DeepPartial<Numbers>): Numbers {
     const message = { ...baseNumbers } as Numbers;
-    if (object.double !== undefined && object.double !== null) {
-      message.double = object.double;
-    } else {
-      message.double = 0;
-    }
-    if (object.float !== undefined && object.float !== null) {
-      message.float = object.float;
-    } else {
-      message.float = 0;
-    }
-    if (object.int32 !== undefined && object.int32 !== null) {
-      message.int32 = object.int32;
-    } else {
-      message.int32 = 0;
-    }
-    if (object.int64 !== undefined && object.int64 !== null) {
-      message.int64 = object.int64;
-    } else {
-      message.int64 = 0;
-    }
-    if (object.uint32 !== undefined && object.uint32 !== null) {
-      message.uint32 = object.uint32;
-    } else {
-      message.uint32 = 0;
-    }
-    if (object.uint64 !== undefined && object.uint64 !== null) {
-      message.uint64 = object.uint64;
-    } else {
-      message.uint64 = 0;
-    }
-    if (object.sint32 !== undefined && object.sint32 !== null) {
-      message.sint32 = object.sint32;
-    } else {
-      message.sint32 = 0;
-    }
-    if (object.sint64 !== undefined && object.sint64 !== null) {
-      message.sint64 = object.sint64;
-    } else {
-      message.sint64 = 0;
-    }
-    if (object.fixed32 !== undefined && object.fixed32 !== null) {
-      message.fixed32 = object.fixed32;
-    } else {
-      message.fixed32 = 0;
-    }
-    if (object.fixed64 !== undefined && object.fixed64 !== null) {
-      message.fixed64 = object.fixed64;
-    } else {
-      message.fixed64 = 0;
-    }
-    if (object.sfixed32 !== undefined && object.sfixed32 !== null) {
-      message.sfixed32 = object.sfixed32;
-    } else {
-      message.sfixed32 = 0;
-    }
-    if (object.sfixed64 !== undefined && object.sfixed64 !== null) {
-      message.sfixed64 = object.sfixed64;
-    } else {
-      message.sfixed64 = 0;
-    }
+    message.double = object.double ?? 0;
+    message.float = object.float ?? 0;
+    message.int32 = object.int32 ?? 0;
+    message.int64 = object.int64 ?? 0;
+    message.uint32 = object.uint32 ?? 0;
+    message.uint64 = object.uint64 ?? 0;
+    message.sint32 = object.sint32 ?? 0;
+    message.sint64 = object.sint64 ?? 0;
+    message.fixed32 = object.fixed32 ?? 0;
+    message.fixed64 = object.fixed64 ?? 0;
+    message.sfixed32 = object.sfixed32 ?? 0;
+    message.sfixed64 = object.sfixed64 ?? 0;
     return message;
   },
 };
diff --git a/integration/simple-optionals/thing.ts b/integration/simple-optionals/thing.ts
index 609e9bc3e..4ae43b0b7 100644
--- a/integration/simple-optionals/thing.ts
+++ b/integration/simple-optionals/thing.ts
@@ -55,11 +55,7 @@ export const ImportedThing = {
 
   fromPartial(object: DeepPartial<ImportedThing>): ImportedThing {
     const message = { ...baseImportedThing } as ImportedThing;
-    if (object.createdAt !== undefined && object.createdAt !== null) {
-      message.createdAt = object.createdAt;
-    } else {
-      message.createdAt = undefined;
-    }
+    message.createdAt = object.createdAt ?? undefined;
     return message;
   },
 };
diff --git a/integration/simple-proto2/simple.ts b/integration/simple-proto2/simple.ts
index 3e56567d4..6a675359c 100644
--- a/integration/simple-proto2/simple.ts
+++ b/integration/simple-proto2/simple.ts
@@ -86,11 +86,7 @@ export const Issue56 = {
 
   fromPartial(object: DeepPartial<Issue56>): Issue56 {
     const message = { ...baseIssue56 } as Issue56;
-    if (object.test !== undefined && object.test !== null) {
-      message.test = object.test;
-    } else {
-      message.test = 1;
-    }
+    message.test = object.test ?? 1;
     return message;
   },
 };
diff --git a/integration/simple-snake/google/protobuf/timestamp.ts b/integration/simple-snake/google/protobuf/timestamp.ts
index 52ea73adb..89f9a4fdb 100644
--- a/integration/simple-snake/google/protobuf/timestamp.ts
+++ b/integration/simple-snake/google/protobuf/timestamp.ts
@@ -162,16 +162,8 @@ export const Timestamp = {
 
   fromPartial(object: DeepPartial<Timestamp>): Timestamp {
     const message = { ...baseTimestamp } as Timestamp;
-    if (object.seconds !== undefined && object.seconds !== null) {
-      message.seconds = object.seconds;
-    } else {
-      message.seconds = 0;
-    }
-    if (object.nanos !== undefined && object.nanos !== null) {
-      message.nanos = object.nanos;
-    } else {
-      message.nanos = 0;
-    }
+    message.seconds = object.seconds ?? 0;
+    message.nanos = object.nanos ?? 0;
     return message;
   },
 };
diff --git a/integration/simple-snake/google/protobuf/wrappers.ts b/integration/simple-snake/google/protobuf/wrappers.ts
index 92da3e0a8..5f52d3fe7 100644
--- a/integration/simple-snake/google/protobuf/wrappers.ts
+++ b/integration/simple-snake/google/protobuf/wrappers.ts
@@ -140,11 +140,7 @@ export const DoubleValue = {
 
   fromPartial(object: DeepPartial<DoubleValue>): DoubleValue {
     const message = { ...baseDoubleValue } as DoubleValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -195,11 +191,7 @@ export const FloatValue = {
 
   fromPartial(object: DeepPartial<FloatValue>): FloatValue {
     const message = { ...baseFloatValue } as FloatValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -250,11 +242,7 @@ export const Int64Value = {
 
   fromPartial(object: DeepPartial<Int64Value>): Int64Value {
     const message = { ...baseInt64Value } as Int64Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -305,11 +293,7 @@ export const UInt64Value = {
 
   fromPartial(object: DeepPartial<UInt64Value>): UInt64Value {
     const message = { ...baseUInt64Value } as UInt64Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -360,11 +344,7 @@ export const Int32Value = {
 
   fromPartial(object: DeepPartial<Int32Value>): Int32Value {
     const message = { ...baseInt32Value } as Int32Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -415,11 +395,7 @@ export const UInt32Value = {
 
   fromPartial(object: DeepPartial<UInt32Value>): UInt32Value {
     const message = { ...baseUInt32Value } as UInt32Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -470,11 +446,7 @@ export const BoolValue = {
 
   fromPartial(object: DeepPartial<BoolValue>): BoolValue {
     const message = { ...baseBoolValue } as BoolValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = false;
-    }
+    message.value = object.value ?? false;
     return message;
   },
 };
@@ -525,11 +497,7 @@ export const StringValue = {
 
   fromPartial(object: DeepPartial<StringValue>): StringValue {
     const message = { ...baseStringValue } as StringValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = '';
-    }
+    message.value = object.value ?? '';
     return message;
   },
 };
@@ -581,11 +549,7 @@ export const BytesValue = {
 
   fromPartial(object: DeepPartial<BytesValue>): BytesValue {
     const message = { ...baseBytesValue } as BytesValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = new Uint8Array();
-    }
+    message.value = object.value ?? new Uint8Array();
     return message;
   },
 };
diff --git a/integration/simple-snake/import_dir/thing.ts b/integration/simple-snake/import_dir/thing.ts
index 050b04f5a..e482a30b8 100644
--- a/integration/simple-snake/import_dir/thing.ts
+++ b/integration/simple-snake/import_dir/thing.ts
@@ -55,11 +55,7 @@ export const ImportedThing = {
 
   fromPartial(object: DeepPartial<ImportedThing>): ImportedThing {
     const message = { ...baseImportedThing } as ImportedThing;
-    if (object.created_at !== undefined && object.created_at !== null) {
-      message.created_at = object.created_at;
-    } else {
-      message.created_at = undefined;
-    }
+    message.created_at = object.created_at ?? undefined;
     return message;
   },
 };
diff --git a/integration/simple-snake/simple.ts b/integration/simple-snake/simple.ts
index a1c7a5cb4..8db58bdea 100644
--- a/integration/simple-snake/simple.ts
+++ b/integration/simple-snake/simple.ts
@@ -431,50 +431,34 @@ export const Simple = {
 
   fromPartial(object: DeepPartial<Simple>): Simple {
     const message = { ...baseSimple } as Simple;
-    message.grand_children = [];
-    message.coins = [];
-    message.snacks = [];
-    message.old_states = [];
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = 0;
-    }
-    if (object.created_at !== undefined && object.created_at !== null) {
-      message.created_at = object.created_at;
-    } else {
-      message.created_at = undefined;
-    }
+    message.name = object.name ?? '';
+    message.age = object.age ?? 0;
+    message.created_at = object.created_at ?? undefined;
     if (object.child !== undefined && object.child !== null) {
       message.child = Child.fromPartial(object.child);
     } else {
       message.child = undefined;
     }
-    if (object.state !== undefined && object.state !== null) {
-      message.state = object.state;
-    } else {
-      message.state = 0;
-    }
+    message.state = object.state ?? 0;
+    message.grand_children = [];
     if (object.grand_children !== undefined && object.grand_children !== null) {
       for (const e of object.grand_children) {
         message.grand_children.push(Child.fromPartial(e));
       }
     }
+    message.coins = [];
     if (object.coins !== undefined && object.coins !== null) {
       for (const e of object.coins) {
         message.coins.push(e);
       }
     }
+    message.snacks = [];
     if (object.snacks !== undefined && object.snacks !== null) {
       for (const e of object.snacks) {
         message.snacks.push(e);
       }
     }
+    message.old_states = [];
     if (object.old_states !== undefined && object.old_states !== null) {
       for (const e of object.old_states) {
         message.old_states.push(e);
@@ -547,16 +531,8 @@ export const Child = {
 
   fromPartial(object: DeepPartial<Child>): Child {
     const message = { ...baseChild } as Child;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
-    if (object.type !== undefined && object.type !== null) {
-      message.type = object.type;
-    } else {
-      message.type = 0;
-    }
+    message.name = object.name ?? '';
+    message.type = object.type ?? 0;
     return message;
   },
 };
@@ -632,21 +608,13 @@ export const Nested = {
 
   fromPartial(object: DeepPartial<Nested>): Nested {
     const message = { ...baseNested } as Nested;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     if (object.message !== undefined && object.message !== null) {
       message.message = Nested_InnerMessage.fromPartial(object.message);
     } else {
       message.message = undefined;
     }
-    if (object.state !== undefined && object.state !== null) {
-      message.state = object.state;
-    } else {
-      message.state = 0;
-    }
+    message.state = object.state ?? 0;
     return message;
   },
 };
@@ -710,11 +678,7 @@ export const Nested_InnerMessage = {
 
   fromPartial(object: DeepPartial<Nested_InnerMessage>): Nested_InnerMessage {
     const message = { ...baseNested_InnerMessage } as Nested_InnerMessage;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     if (object.deep !== undefined && object.deep !== null) {
       message.deep = Nested_InnerMessage_DeepMessage.fromPartial(object.deep);
     } else {
@@ -770,11 +734,7 @@ export const Nested_InnerMessage_DeepMessage = {
 
   fromPartial(object: DeepPartial<Nested_InnerMessage_DeepMessage>): Nested_InnerMessage_DeepMessage {
     const message = { ...baseNested_InnerMessage_DeepMessage } as Nested_InnerMessage_DeepMessage;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     return message;
   },
 };
@@ -837,16 +797,8 @@ export const OneOfMessage = {
 
   fromPartial(object: DeepPartial<OneOfMessage>): OneOfMessage {
     const message = { ...baseOneOfMessage } as OneOfMessage;
-    if (object.first !== undefined && object.first !== null) {
-      message.first = object.first;
-    } else {
-      message.first = undefined;
-    }
-    if (object.last !== undefined && object.last !== null) {
-      message.last = object.last;
-    } else {
-      message.last = undefined;
-    }
+    message.first = object.first ?? undefined;
+    message.last = object.last ?? undefined;
     return message;
   },
 };
@@ -957,28 +909,16 @@ export const SimpleWithWrappers = {
 
   fromPartial(object: DeepPartial<SimpleWithWrappers>): SimpleWithWrappers {
     const message = { ...baseSimpleWithWrappers } as SimpleWithWrappers;
+    message.name = object.name ?? undefined;
+    message.age = object.age ?? undefined;
+    message.enabled = object.enabled ?? undefined;
     message.coins = [];
-    message.snacks = [];
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = undefined;
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = undefined;
-    }
-    if (object.enabled !== undefined && object.enabled !== null) {
-      message.enabled = object.enabled;
-    } else {
-      message.enabled = undefined;
-    }
     if (object.coins !== undefined && object.coins !== null) {
       for (const e of object.coins) {
         message.coins.push(e);
       }
     }
+    message.snacks = [];
     if (object.snacks !== undefined && object.snacks !== null) {
       for (const e of object.snacks) {
         message.snacks.push(e);
@@ -1034,11 +974,7 @@ export const Entity = {
 
   fromPartial(object: DeepPartial<Entity>): Entity {
     const message = { ...baseEntity } as Entity;
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = 0;
-    }
+    message.id = object.id ?? 0;
     return message;
   },
 };
@@ -1144,8 +1080,6 @@ export const SimpleWithMap = {
   fromPartial(object: DeepPartial<SimpleWithMap>): SimpleWithMap {
     const message = { ...baseSimpleWithMap } as SimpleWithMap;
     message.entitiesById = {};
-    message.nameLookup = {};
-    message.intLookup = {};
     if (object.entitiesById !== undefined && object.entitiesById !== null) {
       Object.entries(object.entitiesById).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -1153,6 +1087,7 @@ export const SimpleWithMap = {
         }
       });
     }
+    message.nameLookup = {};
     if (object.nameLookup !== undefined && object.nameLookup !== null) {
       Object.entries(object.nameLookup).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -1160,6 +1095,7 @@ export const SimpleWithMap = {
         }
       });
     }
+    message.intLookup = {};
     if (object.intLookup !== undefined && object.intLookup !== null) {
       Object.entries(object.intLookup).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -1229,11 +1165,7 @@ export const SimpleWithMap_EntitiesByIdEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_EntitiesByIdEntry>): SimpleWithMap_EntitiesByIdEntry {
     const message = { ...baseSimpleWithMap_EntitiesByIdEntry } as SimpleWithMap_EntitiesByIdEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = 0;
-    }
+    message.key = object.key ?? 0;
     if (object.value !== undefined && object.value !== null) {
       message.value = Entity.fromPartial(object.value);
     } else {
@@ -1301,16 +1233,8 @@ export const SimpleWithMap_NameLookupEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_NameLookupEntry>): SimpleWithMap_NameLookupEntry {
     const message = { ...baseSimpleWithMap_NameLookupEntry } as SimpleWithMap_NameLookupEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = '';
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = '';
-    }
+    message.key = object.key ?? '';
+    message.value = object.value ?? '';
     return message;
   },
 };
@@ -1373,16 +1297,8 @@ export const SimpleWithMap_IntLookupEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_IntLookupEntry>): SimpleWithMap_IntLookupEntry {
     const message = { ...baseSimpleWithMap_IntLookupEntry } as SimpleWithMap_IntLookupEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = 0;
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.key = object.key ?? 0;
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -1513,11 +1429,7 @@ export const SimpleWithSnakeCaseMap_EntitiesByIdEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithSnakeCaseMap_EntitiesByIdEntry>): SimpleWithSnakeCaseMap_EntitiesByIdEntry {
     const message = { ...baseSimpleWithSnakeCaseMap_EntitiesByIdEntry } as SimpleWithSnakeCaseMap_EntitiesByIdEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = 0;
-    }
+    message.key = object.key ?? 0;
     if (object.value !== undefined && object.value !== null) {
       message.value = Entity.fromPartial(object.value);
     } else {
@@ -1573,11 +1485,7 @@ export const PingRequest = {
 
   fromPartial(object: DeepPartial<PingRequest>): PingRequest {
     const message = { ...basePingRequest } as PingRequest;
-    if (object.input !== undefined && object.input !== null) {
-      message.input = object.input;
-    } else {
-      message.input = '';
-    }
+    message.input = object.input ?? '';
     return message;
   },
 };
@@ -1628,11 +1536,7 @@ export const PingResponse = {
 
   fromPartial(object: DeepPartial<PingResponse>): PingResponse {
     const message = { ...basePingResponse } as PingResponse;
-    if (object.output !== undefined && object.output !== null) {
-      message.output = object.output;
-    } else {
-      message.output = '';
-    }
+    message.output = object.output ?? '';
     return message;
   },
 };
@@ -1828,66 +1732,18 @@ export const Numbers = {
 
   fromPartial(object: DeepPartial<Numbers>): Numbers {
     const message = { ...baseNumbers } as Numbers;
-    if (object.double !== undefined && object.double !== null) {
-      message.double = object.double;
-    } else {
-      message.double = 0;
-    }
-    if (object.float !== undefined && object.float !== null) {
-      message.float = object.float;
-    } else {
-      message.float = 0;
-    }
-    if (object.int32 !== undefined && object.int32 !== null) {
-      message.int32 = object.int32;
-    } else {
-      message.int32 = 0;
-    }
-    if (object.int64 !== undefined && object.int64 !== null) {
-      message.int64 = object.int64;
-    } else {
-      message.int64 = 0;
-    }
-    if (object.uint32 !== undefined && object.uint32 !== null) {
-      message.uint32 = object.uint32;
-    } else {
-      message.uint32 = 0;
-    }
-    if (object.uint64 !== undefined && object.uint64 !== null) {
-      message.uint64 = object.uint64;
-    } else {
-      message.uint64 = 0;
-    }
-    if (object.sint32 !== undefined && object.sint32 !== null) {
-      message.sint32 = object.sint32;
-    } else {
-      message.sint32 = 0;
-    }
-    if (object.sint64 !== undefined && object.sint64 !== null) {
-      message.sint64 = object.sint64;
-    } else {
-      message.sint64 = 0;
-    }
-    if (object.fixed32 !== undefined && object.fixed32 !== null) {
-      message.fixed32 = object.fixed32;
-    } else {
-      message.fixed32 = 0;
-    }
-    if (object.fixed64 !== undefined && object.fixed64 !== null) {
-      message.fixed64 = object.fixed64;
-    } else {
-      message.fixed64 = 0;
-    }
-    if (object.sfixed32 !== undefined && object.sfixed32 !== null) {
-      message.sfixed32 = object.sfixed32;
-    } else {
-      message.sfixed32 = 0;
-    }
-    if (object.sfixed64 !== undefined && object.sfixed64 !== null) {
-      message.sfixed64 = object.sfixed64;
-    } else {
-      message.sfixed64 = 0;
-    }
+    message.double = object.double ?? 0;
+    message.float = object.float ?? 0;
+    message.int32 = object.int32 ?? 0;
+    message.int64 = object.int64 ?? 0;
+    message.uint32 = object.uint32 ?? 0;
+    message.uint64 = object.uint64 ?? 0;
+    message.sint32 = object.sint32 ?? 0;
+    message.sint64 = object.sint64 ?? 0;
+    message.fixed32 = object.fixed32 ?? 0;
+    message.fixed64 = object.fixed64 ?? 0;
+    message.sfixed32 = object.sfixed32 ?? 0;
+    message.sfixed64 = object.sfixed64 ?? 0;
     return message;
   },
 };
diff --git a/integration/simple-string-enums/simple.ts b/integration/simple-string-enums/simple.ts
index 8a1d9dcf5..beed80d91 100644
--- a/integration/simple-string-enums/simple.ts
+++ b/integration/simple-string-enums/simple.ts
@@ -146,17 +146,9 @@ export const Simple = {
 
   fromPartial(object: DeepPartial<Simple>): Simple {
     const message = { ...baseSimple } as Simple;
+    message.name = object.name ?? '';
+    message.state = object.state ?? StateEnum.UNKNOWN;
     message.states = [];
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
-    if (object.state !== undefined && object.state !== null) {
-      message.state = object.state;
-    } else {
-      message.state = StateEnum.UNKNOWN;
-    }
     if (object.states !== undefined && object.states !== null) {
       for (const e of object.states) {
         message.states.push(e);
diff --git a/integration/simple-unrecognized-enum/google/protobuf/timestamp.ts b/integration/simple-unrecognized-enum/google/protobuf/timestamp.ts
index 52ea73adb..89f9a4fdb 100644
--- a/integration/simple-unrecognized-enum/google/protobuf/timestamp.ts
+++ b/integration/simple-unrecognized-enum/google/protobuf/timestamp.ts
@@ -162,16 +162,8 @@ export const Timestamp = {
 
   fromPartial(object: DeepPartial<Timestamp>): Timestamp {
     const message = { ...baseTimestamp } as Timestamp;
-    if (object.seconds !== undefined && object.seconds !== null) {
-      message.seconds = object.seconds;
-    } else {
-      message.seconds = 0;
-    }
-    if (object.nanos !== undefined && object.nanos !== null) {
-      message.nanos = object.nanos;
-    } else {
-      message.nanos = 0;
-    }
+    message.seconds = object.seconds ?? 0;
+    message.nanos = object.nanos ?? 0;
     return message;
   },
 };
diff --git a/integration/simple-unrecognized-enum/google/protobuf/wrappers.ts b/integration/simple-unrecognized-enum/google/protobuf/wrappers.ts
index 92da3e0a8..5f52d3fe7 100644
--- a/integration/simple-unrecognized-enum/google/protobuf/wrappers.ts
+++ b/integration/simple-unrecognized-enum/google/protobuf/wrappers.ts
@@ -140,11 +140,7 @@ export const DoubleValue = {
 
   fromPartial(object: DeepPartial<DoubleValue>): DoubleValue {
     const message = { ...baseDoubleValue } as DoubleValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -195,11 +191,7 @@ export const FloatValue = {
 
   fromPartial(object: DeepPartial<FloatValue>): FloatValue {
     const message = { ...baseFloatValue } as FloatValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -250,11 +242,7 @@ export const Int64Value = {
 
   fromPartial(object: DeepPartial<Int64Value>): Int64Value {
     const message = { ...baseInt64Value } as Int64Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -305,11 +293,7 @@ export const UInt64Value = {
 
   fromPartial(object: DeepPartial<UInt64Value>): UInt64Value {
     const message = { ...baseUInt64Value } as UInt64Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -360,11 +344,7 @@ export const Int32Value = {
 
   fromPartial(object: DeepPartial<Int32Value>): Int32Value {
     const message = { ...baseInt32Value } as Int32Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -415,11 +395,7 @@ export const UInt32Value = {
 
   fromPartial(object: DeepPartial<UInt32Value>): UInt32Value {
     const message = { ...baseUInt32Value } as UInt32Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -470,11 +446,7 @@ export const BoolValue = {
 
   fromPartial(object: DeepPartial<BoolValue>): BoolValue {
     const message = { ...baseBoolValue } as BoolValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = false;
-    }
+    message.value = object.value ?? false;
     return message;
   },
 };
@@ -525,11 +497,7 @@ export const StringValue = {
 
   fromPartial(object: DeepPartial<StringValue>): StringValue {
     const message = { ...baseStringValue } as StringValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = '';
-    }
+    message.value = object.value ?? '';
     return message;
   },
 };
@@ -581,11 +549,7 @@ export const BytesValue = {
 
   fromPartial(object: DeepPartial<BytesValue>): BytesValue {
     const message = { ...baseBytesValue } as BytesValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = new Uint8Array();
-    }
+    message.value = object.value ?? new Uint8Array();
     return message;
   },
 };
diff --git a/integration/simple-unrecognized-enum/import_dir/thing.ts b/integration/simple-unrecognized-enum/import_dir/thing.ts
index 9c777434d..5ba6da998 100644
--- a/integration/simple-unrecognized-enum/import_dir/thing.ts
+++ b/integration/simple-unrecognized-enum/import_dir/thing.ts
@@ -55,11 +55,7 @@ export const ImportedThing = {
 
   fromPartial(object: DeepPartial<ImportedThing>): ImportedThing {
     const message = { ...baseImportedThing } as ImportedThing;
-    if (object.createdAt !== undefined && object.createdAt !== null) {
-      message.createdAt = object.createdAt;
-    } else {
-      message.createdAt = undefined;
-    }
+    message.createdAt = object.createdAt ?? undefined;
     return message;
   },
 };
diff --git a/integration/simple-unrecognized-enum/simple.ts b/integration/simple-unrecognized-enum/simple.ts
index 58cf9a554..bd45e247a 100644
--- a/integration/simple-unrecognized-enum/simple.ts
+++ b/integration/simple-unrecognized-enum/simple.ts
@@ -422,50 +422,34 @@ export const Simple = {
 
   fromPartial(object: DeepPartial<Simple>): Simple {
     const message = { ...baseSimple } as Simple;
-    message.grandChildren = [];
-    message.coins = [];
-    message.snacks = [];
-    message.oldStates = [];
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = 0;
-    }
-    if (object.createdAt !== undefined && object.createdAt !== null) {
-      message.createdAt = object.createdAt;
-    } else {
-      message.createdAt = undefined;
-    }
+    message.name = object.name ?? '';
+    message.age = object.age ?? 0;
+    message.createdAt = object.createdAt ?? undefined;
     if (object.child !== undefined && object.child !== null) {
       message.child = Child.fromPartial(object.child);
     } else {
       message.child = undefined;
     }
-    if (object.state !== undefined && object.state !== null) {
-      message.state = object.state;
-    } else {
-      message.state = 0;
-    }
+    message.state = object.state ?? 0;
+    message.grandChildren = [];
     if (object.grandChildren !== undefined && object.grandChildren !== null) {
       for (const e of object.grandChildren) {
         message.grandChildren.push(Child.fromPartial(e));
       }
     }
+    message.coins = [];
     if (object.coins !== undefined && object.coins !== null) {
       for (const e of object.coins) {
         message.coins.push(e);
       }
     }
+    message.snacks = [];
     if (object.snacks !== undefined && object.snacks !== null) {
       for (const e of object.snacks) {
         message.snacks.push(e);
       }
     }
+    message.oldStates = [];
     if (object.oldStates !== undefined && object.oldStates !== null) {
       for (const e of object.oldStates) {
         message.oldStates.push(e);
@@ -538,16 +522,8 @@ export const Child = {
 
   fromPartial(object: DeepPartial<Child>): Child {
     const message = { ...baseChild } as Child;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
-    if (object.type !== undefined && object.type !== null) {
-      message.type = object.type;
-    } else {
-      message.type = 0;
-    }
+    message.name = object.name ?? '';
+    message.type = object.type ?? 0;
     return message;
   },
 };
@@ -623,21 +599,13 @@ export const Nested = {
 
   fromPartial(object: DeepPartial<Nested>): Nested {
     const message = { ...baseNested } as Nested;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     if (object.message !== undefined && object.message !== null) {
       message.message = Nested_InnerMessage.fromPartial(object.message);
     } else {
       message.message = undefined;
     }
-    if (object.state !== undefined && object.state !== null) {
-      message.state = object.state;
-    } else {
-      message.state = 0;
-    }
+    message.state = object.state ?? 0;
     return message;
   },
 };
@@ -701,11 +669,7 @@ export const Nested_InnerMessage = {
 
   fromPartial(object: DeepPartial<Nested_InnerMessage>): Nested_InnerMessage {
     const message = { ...baseNested_InnerMessage } as Nested_InnerMessage;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     if (object.deep !== undefined && object.deep !== null) {
       message.deep = Nested_InnerMessage_DeepMessage.fromPartial(object.deep);
     } else {
@@ -761,11 +725,7 @@ export const Nested_InnerMessage_DeepMessage = {
 
   fromPartial(object: DeepPartial<Nested_InnerMessage_DeepMessage>): Nested_InnerMessage_DeepMessage {
     const message = { ...baseNested_InnerMessage_DeepMessage } as Nested_InnerMessage_DeepMessage;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     return message;
   },
 };
@@ -828,16 +788,8 @@ export const OneOfMessage = {
 
   fromPartial(object: DeepPartial<OneOfMessage>): OneOfMessage {
     const message = { ...baseOneOfMessage } as OneOfMessage;
-    if (object.first !== undefined && object.first !== null) {
-      message.first = object.first;
-    } else {
-      message.first = undefined;
-    }
-    if (object.last !== undefined && object.last !== null) {
-      message.last = object.last;
-    } else {
-      message.last = undefined;
-    }
+    message.first = object.first ?? undefined;
+    message.last = object.last ?? undefined;
     return message;
   },
 };
@@ -948,28 +900,16 @@ export const SimpleWithWrappers = {
 
   fromPartial(object: DeepPartial<SimpleWithWrappers>): SimpleWithWrappers {
     const message = { ...baseSimpleWithWrappers } as SimpleWithWrappers;
+    message.name = object.name ?? undefined;
+    message.age = object.age ?? undefined;
+    message.enabled = object.enabled ?? undefined;
     message.coins = [];
-    message.snacks = [];
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = undefined;
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = undefined;
-    }
-    if (object.enabled !== undefined && object.enabled !== null) {
-      message.enabled = object.enabled;
-    } else {
-      message.enabled = undefined;
-    }
     if (object.coins !== undefined && object.coins !== null) {
       for (const e of object.coins) {
         message.coins.push(e);
       }
     }
+    message.snacks = [];
     if (object.snacks !== undefined && object.snacks !== null) {
       for (const e of object.snacks) {
         message.snacks.push(e);
@@ -1025,11 +965,7 @@ export const Entity = {
 
   fromPartial(object: DeepPartial<Entity>): Entity {
     const message = { ...baseEntity } as Entity;
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = 0;
-    }
+    message.id = object.id ?? 0;
     return message;
   },
 };
@@ -1135,8 +1071,6 @@ export const SimpleWithMap = {
   fromPartial(object: DeepPartial<SimpleWithMap>): SimpleWithMap {
     const message = { ...baseSimpleWithMap } as SimpleWithMap;
     message.entitiesById = {};
-    message.nameLookup = {};
-    message.intLookup = {};
     if (object.entitiesById !== undefined && object.entitiesById !== null) {
       Object.entries(object.entitiesById).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -1144,6 +1078,7 @@ export const SimpleWithMap = {
         }
       });
     }
+    message.nameLookup = {};
     if (object.nameLookup !== undefined && object.nameLookup !== null) {
       Object.entries(object.nameLookup).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -1151,6 +1086,7 @@ export const SimpleWithMap = {
         }
       });
     }
+    message.intLookup = {};
     if (object.intLookup !== undefined && object.intLookup !== null) {
       Object.entries(object.intLookup).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -1220,11 +1156,7 @@ export const SimpleWithMap_EntitiesByIdEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_EntitiesByIdEntry>): SimpleWithMap_EntitiesByIdEntry {
     const message = { ...baseSimpleWithMap_EntitiesByIdEntry } as SimpleWithMap_EntitiesByIdEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = 0;
-    }
+    message.key = object.key ?? 0;
     if (object.value !== undefined && object.value !== null) {
       message.value = Entity.fromPartial(object.value);
     } else {
@@ -1292,16 +1224,8 @@ export const SimpleWithMap_NameLookupEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_NameLookupEntry>): SimpleWithMap_NameLookupEntry {
     const message = { ...baseSimpleWithMap_NameLookupEntry } as SimpleWithMap_NameLookupEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = '';
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = '';
-    }
+    message.key = object.key ?? '';
+    message.value = object.value ?? '';
     return message;
   },
 };
@@ -1364,16 +1288,8 @@ export const SimpleWithMap_IntLookupEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_IntLookupEntry>): SimpleWithMap_IntLookupEntry {
     const message = { ...baseSimpleWithMap_IntLookupEntry } as SimpleWithMap_IntLookupEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = 0;
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.key = object.key ?? 0;
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -1504,11 +1420,7 @@ export const SimpleWithSnakeCaseMap_EntitiesByIdEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithSnakeCaseMap_EntitiesByIdEntry>): SimpleWithSnakeCaseMap_EntitiesByIdEntry {
     const message = { ...baseSimpleWithSnakeCaseMap_EntitiesByIdEntry } as SimpleWithSnakeCaseMap_EntitiesByIdEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = 0;
-    }
+    message.key = object.key ?? 0;
     if (object.value !== undefined && object.value !== null) {
       message.value = Entity.fromPartial(object.value);
     } else {
@@ -1564,11 +1476,7 @@ export const PingRequest = {
 
   fromPartial(object: DeepPartial<PingRequest>): PingRequest {
     const message = { ...basePingRequest } as PingRequest;
-    if (object.input !== undefined && object.input !== null) {
-      message.input = object.input;
-    } else {
-      message.input = '';
-    }
+    message.input = object.input ?? '';
     return message;
   },
 };
@@ -1619,11 +1527,7 @@ export const PingResponse = {
 
   fromPartial(object: DeepPartial<PingResponse>): PingResponse {
     const message = { ...basePingResponse } as PingResponse;
-    if (object.output !== undefined && object.output !== null) {
-      message.output = object.output;
-    } else {
-      message.output = '';
-    }
+    message.output = object.output ?? '';
     return message;
   },
 };
@@ -1819,66 +1723,18 @@ export const Numbers = {
 
   fromPartial(object: DeepPartial<Numbers>): Numbers {
     const message = { ...baseNumbers } as Numbers;
-    if (object.double !== undefined && object.double !== null) {
-      message.double = object.double;
-    } else {
-      message.double = 0;
-    }
-    if (object.float !== undefined && object.float !== null) {
-      message.float = object.float;
-    } else {
-      message.float = 0;
-    }
-    if (object.int32 !== undefined && object.int32 !== null) {
-      message.int32 = object.int32;
-    } else {
-      message.int32 = 0;
-    }
-    if (object.int64 !== undefined && object.int64 !== null) {
-      message.int64 = object.int64;
-    } else {
-      message.int64 = 0;
-    }
-    if (object.uint32 !== undefined && object.uint32 !== null) {
-      message.uint32 = object.uint32;
-    } else {
-      message.uint32 = 0;
-    }
-    if (object.uint64 !== undefined && object.uint64 !== null) {
-      message.uint64 = object.uint64;
-    } else {
-      message.uint64 = 0;
-    }
-    if (object.sint32 !== undefined && object.sint32 !== null) {
-      message.sint32 = object.sint32;
-    } else {
-      message.sint32 = 0;
-    }
-    if (object.sint64 !== undefined && object.sint64 !== null) {
-      message.sint64 = object.sint64;
-    } else {
-      message.sint64 = 0;
-    }
-    if (object.fixed32 !== undefined && object.fixed32 !== null) {
-      message.fixed32 = object.fixed32;
-    } else {
-      message.fixed32 = 0;
-    }
-    if (object.fixed64 !== undefined && object.fixed64 !== null) {
-      message.fixed64 = object.fixed64;
-    } else {
-      message.fixed64 = 0;
-    }
-    if (object.sfixed32 !== undefined && object.sfixed32 !== null) {
-      message.sfixed32 = object.sfixed32;
-    } else {
-      message.sfixed32 = 0;
-    }
-    if (object.sfixed64 !== undefined && object.sfixed64 !== null) {
-      message.sfixed64 = object.sfixed64;
-    } else {
-      message.sfixed64 = 0;
-    }
+    message.double = object.double ?? 0;
+    message.float = object.float ?? 0;
+    message.int32 = object.int32 ?? 0;
+    message.int64 = object.int64 ?? 0;
+    message.uint32 = object.uint32 ?? 0;
+    message.uint64 = object.uint64 ?? 0;
+    message.sint32 = object.sint32 ?? 0;
+    message.sint64 = object.sint64 ?? 0;
+    message.fixed32 = object.fixed32 ?? 0;
+    message.fixed64 = object.fixed64 ?? 0;
+    message.sfixed32 = object.sfixed32 ?? 0;
+    message.sfixed64 = object.sfixed64 ?? 0;
     return message;
   },
 };
diff --git a/integration/simple/google/protobuf/timestamp.ts b/integration/simple/google/protobuf/timestamp.ts
index b62358285..a39e45400 100644
--- a/integration/simple/google/protobuf/timestamp.ts
+++ b/integration/simple/google/protobuf/timestamp.ts
@@ -171,16 +171,8 @@ export const Timestamp = {
 
   fromPartial(object: DeepPartial<Timestamp>): Timestamp {
     const message = { ...baseTimestamp } as Timestamp;
-    if (object.seconds !== undefined && object.seconds !== null) {
-      message.seconds = object.seconds;
-    } else {
-      message.seconds = 0;
-    }
-    if (object.nanos !== undefined && object.nanos !== null) {
-      message.nanos = object.nanos;
-    } else {
-      message.nanos = 0;
-    }
+    message.seconds = object.seconds ?? 0;
+    message.nanos = object.nanos ?? 0;
     return message;
   },
 };
diff --git a/integration/simple/google/protobuf/wrappers.ts b/integration/simple/google/protobuf/wrappers.ts
index 92da3e0a8..5f52d3fe7 100644
--- a/integration/simple/google/protobuf/wrappers.ts
+++ b/integration/simple/google/protobuf/wrappers.ts
@@ -140,11 +140,7 @@ export const DoubleValue = {
 
   fromPartial(object: DeepPartial<DoubleValue>): DoubleValue {
     const message = { ...baseDoubleValue } as DoubleValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -195,11 +191,7 @@ export const FloatValue = {
 
   fromPartial(object: DeepPartial<FloatValue>): FloatValue {
     const message = { ...baseFloatValue } as FloatValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -250,11 +242,7 @@ export const Int64Value = {
 
   fromPartial(object: DeepPartial<Int64Value>): Int64Value {
     const message = { ...baseInt64Value } as Int64Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -305,11 +293,7 @@ export const UInt64Value = {
 
   fromPartial(object: DeepPartial<UInt64Value>): UInt64Value {
     const message = { ...baseUInt64Value } as UInt64Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -360,11 +344,7 @@ export const Int32Value = {
 
   fromPartial(object: DeepPartial<Int32Value>): Int32Value {
     const message = { ...baseInt32Value } as Int32Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -415,11 +395,7 @@ export const UInt32Value = {
 
   fromPartial(object: DeepPartial<UInt32Value>): UInt32Value {
     const message = { ...baseUInt32Value } as UInt32Value;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -470,11 +446,7 @@ export const BoolValue = {
 
   fromPartial(object: DeepPartial<BoolValue>): BoolValue {
     const message = { ...baseBoolValue } as BoolValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = false;
-    }
+    message.value = object.value ?? false;
     return message;
   },
 };
@@ -525,11 +497,7 @@ export const StringValue = {
 
   fromPartial(object: DeepPartial<StringValue>): StringValue {
     const message = { ...baseStringValue } as StringValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = '';
-    }
+    message.value = object.value ?? '';
     return message;
   },
 };
@@ -581,11 +549,7 @@ export const BytesValue = {
 
   fromPartial(object: DeepPartial<BytesValue>): BytesValue {
     const message = { ...baseBytesValue } as BytesValue;
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = new Uint8Array();
-    }
+    message.value = object.value ?? new Uint8Array();
     return message;
   },
 };
diff --git a/integration/simple/google/type/date.ts b/integration/simple/google/type/date.ts
index 722f40458..33b2865a3 100644
--- a/integration/simple/google/type/date.ts
+++ b/integration/simple/google/type/date.ts
@@ -105,21 +105,9 @@ export const DateMessage = {
 
   fromPartial(object: DeepPartial<DateMessage>): DateMessage {
     const message = { ...baseDateMessage } as DateMessage;
-    if (object.year !== undefined && object.year !== null) {
-      message.year = object.year;
-    } else {
-      message.year = 0;
-    }
-    if (object.month !== undefined && object.month !== null) {
-      message.month = object.month;
-    } else {
-      message.month = 0;
-    }
-    if (object.day !== undefined && object.day !== null) {
-      message.day = object.day;
-    } else {
-      message.day = 0;
-    }
+    message.year = object.year ?? 0;
+    message.month = object.month ?? 0;
+    message.day = object.day ?? 0;
     return message;
   },
 };
diff --git a/integration/simple/import_dir/thing.ts b/integration/simple/import_dir/thing.ts
index 9c777434d..5ba6da998 100644
--- a/integration/simple/import_dir/thing.ts
+++ b/integration/simple/import_dir/thing.ts
@@ -55,11 +55,7 @@ export const ImportedThing = {
 
   fromPartial(object: DeepPartial<ImportedThing>): ImportedThing {
     const message = { ...baseImportedThing } as ImportedThing;
-    if (object.createdAt !== undefined && object.createdAt !== null) {
-      message.createdAt = object.createdAt;
-    } else {
-      message.createdAt = undefined;
-    }
+    message.createdAt = object.createdAt ?? undefined;
     return message;
   },
 };
diff --git a/integration/simple/simple.ts b/integration/simple/simple.ts
index 6478da445..5d5cf1861 100644
--- a/integration/simple/simple.ts
+++ b/integration/simple/simple.ts
@@ -524,51 +524,34 @@ export const Simple = {
 
   fromPartial(object: DeepPartial<Simple>): Simple {
     const message = { ...baseSimple } as Simple;
-    message.grandChildren = [];
-    message.coins = [];
-    message.snacks = [];
-    message.oldStates = [];
-    message.blobs = [];
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = 0;
-    }
-    if (object.createdAt !== undefined && object.createdAt !== null) {
-      message.createdAt = object.createdAt;
-    } else {
-      message.createdAt = undefined;
-    }
+    message.name = object.name ?? '';
+    message.age = object.age ?? 0;
+    message.createdAt = object.createdAt ?? undefined;
     if (object.child !== undefined && object.child !== null) {
       message.child = Child.fromPartial(object.child);
     } else {
       message.child = undefined;
     }
-    if (object.state !== undefined && object.state !== null) {
-      message.state = object.state;
-    } else {
-      message.state = 0;
-    }
+    message.state = object.state ?? 0;
+    message.grandChildren = [];
     if (object.grandChildren !== undefined && object.grandChildren !== null) {
       for (const e of object.grandChildren) {
         message.grandChildren.push(Child.fromPartial(e));
       }
     }
+    message.coins = [];
     if (object.coins !== undefined && object.coins !== null) {
       for (const e of object.coins) {
         message.coins.push(e);
       }
     }
+    message.snacks = [];
     if (object.snacks !== undefined && object.snacks !== null) {
       for (const e of object.snacks) {
         message.snacks.push(e);
       }
     }
+    message.oldStates = [];
     if (object.oldStates !== undefined && object.oldStates !== null) {
       for (const e of object.oldStates) {
         message.oldStates.push(e);
@@ -579,6 +562,7 @@ export const Simple = {
     } else {
       message.thing = undefined;
     }
+    message.blobs = [];
     if (object.blobs !== undefined && object.blobs !== null) {
       for (const e of object.blobs) {
         message.blobs.push(e);
@@ -589,11 +573,7 @@ export const Simple = {
     } else {
       message.birthday = undefined;
     }
-    if (object.blob !== undefined && object.blob !== null) {
-      message.blob = object.blob;
-    } else {
-      message.blob = new Uint8Array();
-    }
+    message.blob = object.blob ?? new Uint8Array();
     return message;
   },
 };
@@ -656,16 +636,8 @@ export const Child = {
 
   fromPartial(object: DeepPartial<Child>): Child {
     const message = { ...baseChild } as Child;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
-    if (object.type !== undefined && object.type !== null) {
-      message.type = object.type;
-    } else {
-      message.type = 0;
-    }
+    message.name = object.name ?? '';
+    message.type = object.type ?? 0;
     return message;
   },
 };
@@ -741,21 +713,13 @@ export const Nested = {
 
   fromPartial(object: DeepPartial<Nested>): Nested {
     const message = { ...baseNested } as Nested;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     if (object.message !== undefined && object.message !== null) {
       message.message = Nested_InnerMessage.fromPartial(object.message);
     } else {
       message.message = undefined;
     }
-    if (object.state !== undefined && object.state !== null) {
-      message.state = object.state;
-    } else {
-      message.state = 0;
-    }
+    message.state = object.state ?? 0;
     return message;
   },
 };
@@ -819,11 +783,7 @@ export const Nested_InnerMessage = {
 
   fromPartial(object: DeepPartial<Nested_InnerMessage>): Nested_InnerMessage {
     const message = { ...baseNested_InnerMessage } as Nested_InnerMessage;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     if (object.deep !== undefined && object.deep !== null) {
       message.deep = Nested_InnerMessage_DeepMessage.fromPartial(object.deep);
     } else {
@@ -879,11 +839,7 @@ export const Nested_InnerMessage_DeepMessage = {
 
   fromPartial(object: DeepPartial<Nested_InnerMessage_DeepMessage>): Nested_InnerMessage_DeepMessage {
     const message = { ...baseNested_InnerMessage_DeepMessage } as Nested_InnerMessage_DeepMessage;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
+    message.name = object.name ?? '';
     return message;
   },
 };
@@ -946,16 +902,8 @@ export const OneOfMessage = {
 
   fromPartial(object: DeepPartial<OneOfMessage>): OneOfMessage {
     const message = { ...baseOneOfMessage } as OneOfMessage;
-    if (object.first !== undefined && object.first !== null) {
-      message.first = object.first;
-    } else {
-      message.first = undefined;
-    }
-    if (object.last !== undefined && object.last !== null) {
-      message.last = object.last;
-    } else {
-      message.last = undefined;
-    }
+    message.first = object.first ?? undefined;
+    message.last = object.last ?? undefined;
     return message;
   },
 };
@@ -1078,38 +1026,22 @@ export const SimpleWithWrappers = {
 
   fromPartial(object: DeepPartial<SimpleWithWrappers>): SimpleWithWrappers {
     const message = { ...baseSimpleWithWrappers } as SimpleWithWrappers;
+    message.name = object.name ?? undefined;
+    message.age = object.age ?? undefined;
+    message.enabled = object.enabled ?? undefined;
     message.coins = [];
-    message.snacks = [];
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = undefined;
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = undefined;
-    }
-    if (object.enabled !== undefined && object.enabled !== null) {
-      message.enabled = object.enabled;
-    } else {
-      message.enabled = undefined;
-    }
     if (object.coins !== undefined && object.coins !== null) {
       for (const e of object.coins) {
         message.coins.push(e);
       }
     }
+    message.snacks = [];
     if (object.snacks !== undefined && object.snacks !== null) {
       for (const e of object.snacks) {
         message.snacks.push(e);
       }
     }
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = undefined;
-    }
+    message.id = object.id ?? undefined;
     return message;
   },
 };
@@ -1160,11 +1092,7 @@ export const Entity = {
 
   fromPartial(object: DeepPartial<Entity>): Entity {
     const message = { ...baseEntity } as Entity;
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = 0;
-    }
+    message.id = object.id ?? 0;
     return message;
   },
 };
@@ -1338,11 +1266,6 @@ export const SimpleWithMap = {
   fromPartial(object: DeepPartial<SimpleWithMap>): SimpleWithMap {
     const message = { ...baseSimpleWithMap } as SimpleWithMap;
     message.entitiesById = {};
-    message.nameLookup = {};
-    message.intLookup = {};
-    message.mapOfTimestamps = {};
-    message.mapOfBytes = {};
-    message.mapOfStringValues = {};
     if (object.entitiesById !== undefined && object.entitiesById !== null) {
       Object.entries(object.entitiesById).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -1350,6 +1273,7 @@ export const SimpleWithMap = {
         }
       });
     }
+    message.nameLookup = {};
     if (object.nameLookup !== undefined && object.nameLookup !== null) {
       Object.entries(object.nameLookup).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -1357,6 +1281,7 @@ export const SimpleWithMap = {
         }
       });
     }
+    message.intLookup = {};
     if (object.intLookup !== undefined && object.intLookup !== null) {
       Object.entries(object.intLookup).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -1364,6 +1289,7 @@ export const SimpleWithMap = {
         }
       });
     }
+    message.mapOfTimestamps = {};
     if (object.mapOfTimestamps !== undefined && object.mapOfTimestamps !== null) {
       Object.entries(object.mapOfTimestamps).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -1371,6 +1297,7 @@ export const SimpleWithMap = {
         }
       });
     }
+    message.mapOfBytes = {};
     if (object.mapOfBytes !== undefined && object.mapOfBytes !== null) {
       Object.entries(object.mapOfBytes).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -1378,6 +1305,7 @@ export const SimpleWithMap = {
         }
       });
     }
+    message.mapOfStringValues = {};
     if (object.mapOfStringValues !== undefined && object.mapOfStringValues !== null) {
       Object.entries(object.mapOfStringValues).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -1447,11 +1375,7 @@ export const SimpleWithMap_EntitiesByIdEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_EntitiesByIdEntry>): SimpleWithMap_EntitiesByIdEntry {
     const message = { ...baseSimpleWithMap_EntitiesByIdEntry } as SimpleWithMap_EntitiesByIdEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = 0;
-    }
+    message.key = object.key ?? 0;
     if (object.value !== undefined && object.value !== null) {
       message.value = Entity.fromPartial(object.value);
     } else {
@@ -1519,16 +1443,8 @@ export const SimpleWithMap_NameLookupEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_NameLookupEntry>): SimpleWithMap_NameLookupEntry {
     const message = { ...baseSimpleWithMap_NameLookupEntry } as SimpleWithMap_NameLookupEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = '';
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = '';
-    }
+    message.key = object.key ?? '';
+    message.value = object.value ?? '';
     return message;
   },
 };
@@ -1591,16 +1507,8 @@ export const SimpleWithMap_IntLookupEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_IntLookupEntry>): SimpleWithMap_IntLookupEntry {
     const message = { ...baseSimpleWithMap_IntLookupEntry } as SimpleWithMap_IntLookupEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = 0;
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.key = object.key ?? 0;
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -1663,16 +1571,8 @@ export const SimpleWithMap_MapOfTimestampsEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_MapOfTimestampsEntry>): SimpleWithMap_MapOfTimestampsEntry {
     const message = { ...baseSimpleWithMap_MapOfTimestampsEntry } as SimpleWithMap_MapOfTimestampsEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = '';
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = undefined;
-    }
+    message.key = object.key ?? '';
+    message.value = object.value ?? undefined;
     return message;
   },
 };
@@ -1736,16 +1636,8 @@ export const SimpleWithMap_MapOfBytesEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_MapOfBytesEntry>): SimpleWithMap_MapOfBytesEntry {
     const message = { ...baseSimpleWithMap_MapOfBytesEntry } as SimpleWithMap_MapOfBytesEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = '';
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = new Uint8Array();
-    }
+    message.key = object.key ?? '';
+    message.value = object.value ?? new Uint8Array();
     return message;
   },
 };
@@ -1808,16 +1700,8 @@ export const SimpleWithMap_MapOfStringValuesEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMap_MapOfStringValuesEntry>): SimpleWithMap_MapOfStringValuesEntry {
     const message = { ...baseSimpleWithMap_MapOfStringValuesEntry } as SimpleWithMap_MapOfStringValuesEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = '';
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = undefined;
-    }
+    message.key = object.key ?? '';
+    message.value = object.value ?? undefined;
     return message;
   },
 };
@@ -1948,11 +1832,7 @@ export const SimpleWithSnakeCaseMap_EntitiesByIdEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithSnakeCaseMap_EntitiesByIdEntry>): SimpleWithSnakeCaseMap_EntitiesByIdEntry {
     const message = { ...baseSimpleWithSnakeCaseMap_EntitiesByIdEntry } as SimpleWithSnakeCaseMap_EntitiesByIdEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = 0;
-    }
+    message.key = object.key ?? 0;
     if (object.value !== undefined && object.value !== null) {
       message.value = Entity.fromPartial(object.value);
     } else {
@@ -2088,16 +1968,8 @@ export const SimpleWithMapOfEnums_EnumsByIdEntry = {
 
   fromPartial(object: DeepPartial<SimpleWithMapOfEnums_EnumsByIdEntry>): SimpleWithMapOfEnums_EnumsByIdEntry {
     const message = { ...baseSimpleWithMapOfEnums_EnumsByIdEntry } as SimpleWithMapOfEnums_EnumsByIdEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = 0;
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = 0;
-    }
+    message.key = object.key ?? 0;
+    message.value = object.value ?? 0;
     return message;
   },
 };
@@ -2148,11 +2020,7 @@ export const PingRequest = {
 
   fromPartial(object: DeepPartial<PingRequest>): PingRequest {
     const message = { ...basePingRequest } as PingRequest;
-    if (object.input !== undefined && object.input !== null) {
-      message.input = object.input;
-    } else {
-      message.input = '';
-    }
+    message.input = object.input ?? '';
     return message;
   },
 };
@@ -2203,11 +2071,7 @@ export const PingResponse = {
 
   fromPartial(object: DeepPartial<PingResponse>): PingResponse {
     const message = { ...basePingResponse } as PingResponse;
-    if (object.output !== undefined && object.output !== null) {
-      message.output = object.output;
-    } else {
-      message.output = '';
-    }
+    message.output = object.output ?? '';
     return message;
   },
 };
@@ -2403,66 +2267,18 @@ export const Numbers = {
 
   fromPartial(object: DeepPartial<Numbers>): Numbers {
     const message = { ...baseNumbers } as Numbers;
-    if (object.double !== undefined && object.double !== null) {
-      message.double = object.double;
-    } else {
-      message.double = 0;
-    }
-    if (object.float !== undefined && object.float !== null) {
-      message.float = object.float;
-    } else {
-      message.float = 0;
-    }
-    if (object.int32 !== undefined && object.int32 !== null) {
-      message.int32 = object.int32;
-    } else {
-      message.int32 = 0;
-    }
-    if (object.int64 !== undefined && object.int64 !== null) {
-      message.int64 = object.int64;
-    } else {
-      message.int64 = 0;
-    }
-    if (object.uint32 !== undefined && object.uint32 !== null) {
-      message.uint32 = object.uint32;
-    } else {
-      message.uint32 = 0;
-    }
-    if (object.uint64 !== undefined && object.uint64 !== null) {
-      message.uint64 = object.uint64;
-    } else {
-      message.uint64 = 0;
-    }
-    if (object.sint32 !== undefined && object.sint32 !== null) {
-      message.sint32 = object.sint32;
-    } else {
-      message.sint32 = 0;
-    }
-    if (object.sint64 !== undefined && object.sint64 !== null) {
-      message.sint64 = object.sint64;
-    } else {
-      message.sint64 = 0;
-    }
-    if (object.fixed32 !== undefined && object.fixed32 !== null) {
-      message.fixed32 = object.fixed32;
-    } else {
-      message.fixed32 = 0;
-    }
-    if (object.fixed64 !== undefined && object.fixed64 !== null) {
-      message.fixed64 = object.fixed64;
-    } else {
-      message.fixed64 = 0;
-    }
-    if (object.sfixed32 !== undefined && object.sfixed32 !== null) {
-      message.sfixed32 = object.sfixed32;
-    } else {
-      message.sfixed32 = 0;
-    }
-    if (object.sfixed64 !== undefined && object.sfixed64 !== null) {
-      message.sfixed64 = object.sfixed64;
-    } else {
-      message.sfixed64 = 0;
-    }
+    message.double = object.double ?? 0;
+    message.float = object.float ?? 0;
+    message.int32 = object.int32 ?? 0;
+    message.int64 = object.int64 ?? 0;
+    message.uint32 = object.uint32 ?? 0;
+    message.uint64 = object.uint64 ?? 0;
+    message.sint32 = object.sint32 ?? 0;
+    message.sint64 = object.sint64 ?? 0;
+    message.fixed32 = object.fixed32 ?? 0;
+    message.fixed64 = object.fixed64 ?? 0;
+    message.sfixed32 = object.sfixed32 ?? 0;
+    message.sfixed64 = object.sfixed64 ?? 0;
     return message;
   },
 };
@@ -2587,31 +2403,15 @@ export const SimpleButOptional = {
 
   fromPartial(object: DeepPartial<SimpleButOptional>): SimpleButOptional {
     const message = { ...baseSimpleButOptional } as SimpleButOptional;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = undefined;
-    }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = undefined;
-    }
-    if (object.createdAt !== undefined && object.createdAt !== null) {
-      message.createdAt = object.createdAt;
-    } else {
-      message.createdAt = undefined;
-    }
+    message.name = object.name ?? undefined;
+    message.age = object.age ?? undefined;
+    message.createdAt = object.createdAt ?? undefined;
     if (object.child !== undefined && object.child !== null) {
       message.child = Child.fromPartial(object.child);
     } else {
       message.child = undefined;
     }
-    if (object.state !== undefined && object.state !== null) {
-      message.state = object.state;
-    } else {
-      message.state = undefined;
-    }
+    message.state = object.state ?? undefined;
     if (object.thing !== undefined && object.thing !== null) {
       message.thing = ImportedThing.fromPartial(object.thing);
     } else {
diff --git a/integration/type-registry/foo.ts b/integration/type-registry/foo.ts
index f54103137..a046a04e2 100644
--- a/integration/type-registry/foo.ts
+++ b/integration/type-registry/foo.ts
@@ -64,11 +64,7 @@ export const Foo = {
 
   fromPartial(object: DeepPartial<Foo>): Foo {
     const message = { ...baseFoo } as Foo;
-    if (object.timestamp !== undefined && object.timestamp !== null) {
-      message.timestamp = object.timestamp;
-    } else {
-      message.timestamp = undefined;
-    }
+    message.timestamp = object.timestamp ?? undefined;
     return message;
   },
 };
@@ -123,11 +119,7 @@ export const Foo2 = {
 
   fromPartial(object: DeepPartial<Foo2>): Foo2 {
     const message = { ...baseFoo2 } as Foo2;
-    if (object.timestamp !== undefined && object.timestamp !== null) {
-      message.timestamp = object.timestamp;
-    } else {
-      message.timestamp = undefined;
-    }
+    message.timestamp = object.timestamp ?? undefined;
     return message;
   },
 };
diff --git a/integration/type-registry/google/protobuf/timestamp.ts b/integration/type-registry/google/protobuf/timestamp.ts
index b5a864401..f464d4aae 100644
--- a/integration/type-registry/google/protobuf/timestamp.ts
+++ b/integration/type-registry/google/protobuf/timestamp.ts
@@ -166,16 +166,8 @@ export const Timestamp = {
 
   fromPartial(object: DeepPartial<Timestamp>): Timestamp {
     const message = { ...baseTimestamp } as Timestamp;
-    if (object.seconds !== undefined && object.seconds !== null) {
-      message.seconds = object.seconds;
-    } else {
-      message.seconds = 0;
-    }
-    if (object.nanos !== undefined && object.nanos !== null) {
-      message.nanos = object.nanos;
-    } else {
-      message.nanos = 0;
-    }
+    message.seconds = object.seconds ?? 0;
+    message.nanos = object.nanos ?? 0;
     return message;
   },
 };
diff --git a/integration/use-date-false/google/protobuf/timestamp.ts b/integration/use-date-false/google/protobuf/timestamp.ts
index 52ea73adb..89f9a4fdb 100644
--- a/integration/use-date-false/google/protobuf/timestamp.ts
+++ b/integration/use-date-false/google/protobuf/timestamp.ts
@@ -162,16 +162,8 @@ export const Timestamp = {
 
   fromPartial(object: DeepPartial<Timestamp>): Timestamp {
     const message = { ...baseTimestamp } as Timestamp;
-    if (object.seconds !== undefined && object.seconds !== null) {
-      message.seconds = object.seconds;
-    } else {
-      message.seconds = 0;
-    }
-    if (object.nanos !== undefined && object.nanos !== null) {
-      message.nanos = object.nanos;
-    } else {
-      message.nanos = 0;
-    }
+    message.seconds = object.seconds ?? 0;
+    message.nanos = object.nanos ?? 0;
     return message;
   },
 };
diff --git a/integration/use-date-string/google/protobuf/timestamp.ts b/integration/use-date-string/google/protobuf/timestamp.ts
index 52ea73adb..89f9a4fdb 100644
--- a/integration/use-date-string/google/protobuf/timestamp.ts
+++ b/integration/use-date-string/google/protobuf/timestamp.ts
@@ -162,16 +162,8 @@ export const Timestamp = {
 
   fromPartial(object: DeepPartial<Timestamp>): Timestamp {
     const message = { ...baseTimestamp } as Timestamp;
-    if (object.seconds !== undefined && object.seconds !== null) {
-      message.seconds = object.seconds;
-    } else {
-      message.seconds = 0;
-    }
-    if (object.nanos !== undefined && object.nanos !== null) {
-      message.nanos = object.nanos;
-    } else {
-      message.nanos = 0;
-    }
+    message.seconds = object.seconds ?? 0;
+    message.nanos = object.nanos ?? 0;
     return message;
   },
 };
diff --git a/integration/use-date-string/use-date-string.ts b/integration/use-date-string/use-date-string.ts
index e31c61837..23661339b 100644
--- a/integration/use-date-string/use-date-string.ts
+++ b/integration/use-date-string/use-date-string.ts
@@ -128,28 +128,16 @@ export const Todo = {
 
   fromPartial(object: DeepPartial<Todo>): Todo {
     const message = { ...baseTodo } as Todo;
+    message.id = object.id ?? '';
+    message.timestamp = object.timestamp ?? undefined;
     message.repeatedTimestamp = [];
-    message.mapOfTimestamps = {};
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = '';
-    }
-    if (object.timestamp !== undefined && object.timestamp !== null) {
-      message.timestamp = object.timestamp;
-    } else {
-      message.timestamp = undefined;
-    }
     if (object.repeatedTimestamp !== undefined && object.repeatedTimestamp !== null) {
       for (const e of object.repeatedTimestamp) {
         message.repeatedTimestamp.push(e);
       }
     }
-    if (object.optionalTimestamp !== undefined && object.optionalTimestamp !== null) {
-      message.optionalTimestamp = object.optionalTimestamp;
-    } else {
-      message.optionalTimestamp = undefined;
-    }
+    message.optionalTimestamp = object.optionalTimestamp ?? undefined;
+    message.mapOfTimestamps = {};
     if (object.mapOfTimestamps !== undefined && object.mapOfTimestamps !== null) {
       Object.entries(object.mapOfTimestamps).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -219,16 +207,8 @@ export const Todo_MapOfTimestampsEntry = {
 
   fromPartial(object: DeepPartial<Todo_MapOfTimestampsEntry>): Todo_MapOfTimestampsEntry {
     const message = { ...baseTodo_MapOfTimestampsEntry } as Todo_MapOfTimestampsEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = '';
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = undefined;
-    }
+    message.key = object.key ?? '';
+    message.value = object.value ?? undefined;
     return message;
   },
 };
diff --git a/integration/use-date-true/google/protobuf/timestamp.ts b/integration/use-date-true/google/protobuf/timestamp.ts
index 52ea73adb..89f9a4fdb 100644
--- a/integration/use-date-true/google/protobuf/timestamp.ts
+++ b/integration/use-date-true/google/protobuf/timestamp.ts
@@ -162,16 +162,8 @@ export const Timestamp = {
 
   fromPartial(object: DeepPartial<Timestamp>): Timestamp {
     const message = { ...baseTimestamp } as Timestamp;
-    if (object.seconds !== undefined && object.seconds !== null) {
-      message.seconds = object.seconds;
-    } else {
-      message.seconds = 0;
-    }
-    if (object.nanos !== undefined && object.nanos !== null) {
-      message.nanos = object.nanos;
-    } else {
-      message.nanos = 0;
-    }
+    message.seconds = object.seconds ?? 0;
+    message.nanos = object.nanos ?? 0;
     return message;
   },
 };
diff --git a/integration/use-date-true/use-date-true.ts b/integration/use-date-true/use-date-true.ts
index b8e69f6fc..f535467cf 100644
--- a/integration/use-date-true/use-date-true.ts
+++ b/integration/use-date-true/use-date-true.ts
@@ -128,28 +128,16 @@ export const Todo = {
 
   fromPartial(object: DeepPartial<Todo>): Todo {
     const message = { ...baseTodo } as Todo;
+    message.id = object.id ?? '';
+    message.timestamp = object.timestamp ?? undefined;
     message.repeatedTimestamp = [];
-    message.mapOfTimestamps = {};
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = '';
-    }
-    if (object.timestamp !== undefined && object.timestamp !== null) {
-      message.timestamp = object.timestamp;
-    } else {
-      message.timestamp = undefined;
-    }
     if (object.repeatedTimestamp !== undefined && object.repeatedTimestamp !== null) {
       for (const e of object.repeatedTimestamp) {
         message.repeatedTimestamp.push(e);
       }
     }
-    if (object.optionalTimestamp !== undefined && object.optionalTimestamp !== null) {
-      message.optionalTimestamp = object.optionalTimestamp;
-    } else {
-      message.optionalTimestamp = undefined;
-    }
+    message.optionalTimestamp = object.optionalTimestamp ?? undefined;
+    message.mapOfTimestamps = {};
     if (object.mapOfTimestamps !== undefined && object.mapOfTimestamps !== null) {
       Object.entries(object.mapOfTimestamps).forEach(([key, value]) => {
         if (value !== undefined) {
@@ -219,16 +207,8 @@ export const Todo_MapOfTimestampsEntry = {
 
   fromPartial(object: DeepPartial<Todo_MapOfTimestampsEntry>): Todo_MapOfTimestampsEntry {
     const message = { ...baseTodo_MapOfTimestampsEntry } as Todo_MapOfTimestampsEntry;
-    if (object.key !== undefined && object.key !== null) {
-      message.key = object.key;
-    } else {
-      message.key = '';
-    }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = undefined;
-    }
+    message.key = object.key ?? '';
+    message.value = object.value ?? undefined;
     return message;
   },
 };
diff --git a/integration/vector-tile/vector_tile.ts b/integration/vector-tile/vector_tile.ts
index ff6a2f396..d67538767 100644
--- a/integration/vector-tile/vector_tile.ts
+++ b/integration/vector-tile/vector_tile.ts
@@ -266,41 +266,13 @@ export const Tile_Value = {
 
   fromPartial(object: DeepPartial<Tile_Value>): Tile_Value {
     const message = { ...baseTile_Value } as Tile_Value;
-    if (object.stringValue !== undefined && object.stringValue !== null) {
-      message.stringValue = object.stringValue;
-    } else {
-      message.stringValue = '';
-    }
-    if (object.floatValue !== undefined && object.floatValue !== null) {
-      message.floatValue = object.floatValue;
-    } else {
-      message.floatValue = 0;
-    }
-    if (object.doubleValue !== undefined && object.doubleValue !== null) {
-      message.doubleValue = object.doubleValue;
-    } else {
-      message.doubleValue = 0;
-    }
-    if (object.intValue !== undefined && object.intValue !== null) {
-      message.intValue = object.intValue;
-    } else {
-      message.intValue = 0;
-    }
-    if (object.uintValue !== undefined && object.uintValue !== null) {
-      message.uintValue = object.uintValue;
-    } else {
-      message.uintValue = 0;
-    }
-    if (object.sintValue !== undefined && object.sintValue !== null) {
-      message.sintValue = object.sintValue;
-    } else {
-      message.sintValue = 0;
-    }
-    if (object.boolValue !== undefined && object.boolValue !== null) {
-      message.boolValue = object.boolValue;
-    } else {
-      message.boolValue = false;
-    }
+    message.stringValue = object.stringValue ?? '';
+    message.floatValue = object.floatValue ?? 0;
+    message.doubleValue = object.doubleValue ?? 0;
+    message.intValue = object.intValue ?? 0;
+    message.uintValue = object.uintValue ?? 0;
+    message.sintValue = object.sintValue ?? 0;
+    message.boolValue = object.boolValue ?? false;
     return message;
   },
 };
@@ -417,23 +389,15 @@ export const Tile_Feature = {
 
   fromPartial(object: DeepPartial<Tile_Feature>): Tile_Feature {
     const message = { ...baseTile_Feature } as Tile_Feature;
+    message.id = object.id ?? 0;
     message.tags = [];
-    message.geometry = [];
-    if (object.id !== undefined && object.id !== null) {
-      message.id = object.id;
-    } else {
-      message.id = 0;
-    }
     if (object.tags !== undefined && object.tags !== null) {
       for (const e of object.tags) {
         message.tags.push(e);
       }
     }
-    if (object.type !== undefined && object.type !== null) {
-      message.type = object.type;
-    } else {
-      message.type = 0;
-    }
+    message.type = object.type ?? 0;
+    message.geometry = [];
     if (object.geometry !== undefined && object.geometry !== null) {
       for (const e of object.geometry) {
         message.geometry.push(e);
@@ -567,39 +531,27 @@ export const Tile_Layer = {
 
   fromPartial(object: DeepPartial<Tile_Layer>): Tile_Layer {
     const message = { ...baseTile_Layer } as Tile_Layer;
+    message.version = object.version ?? 0;
+    message.name = object.name ?? '';
     message.features = [];
-    message.keys = [];
-    message.values = [];
-    if (object.version !== undefined && object.version !== null) {
-      message.version = object.version;
-    } else {
-      message.version = 0;
-    }
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = '';
-    }
     if (object.features !== undefined && object.features !== null) {
       for (const e of object.features) {
         message.features.push(Tile_Feature.fromPartial(e));
       }
     }
+    message.keys = [];
     if (object.keys !== undefined && object.keys !== null) {
       for (const e of object.keys) {
         message.keys.push(e);
       }
     }
+    message.values = [];
     if (object.values !== undefined && object.values !== null) {
       for (const e of object.values) {
         message.values.push(Tile_Value.fromPartial(e));
       }
     }
-    if (object.extent !== undefined && object.extent !== null) {
-      message.extent = object.extent;
-    } else {
-      message.extent = 0;
-    }
+    message.extent = object.extent ?? 0;
     return message;
   },
 };
diff --git a/src/main.ts b/src/main.ts
index 25c2827d2..f24269c51 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -1127,7 +1127,6 @@ function generateToJson(ctx: Context, fullName: string, messageDesc: DescriptorP
       chunks.push(code`message.${fieldName} !== undefined && (obj.${fieldName} = ${v});`);
     }
   });
-
   chunks.push(code`return obj;`);
   chunks.push(code`}`);
   return joinCode(chunks, { on: '\n' });
@@ -1144,13 +1143,6 @@ function generateFromPartial(ctx: Context, fullName: string, messageDesc: Descri
       const message = { ...base${fullName} } as ${fullName};
   `);
 
-  // initialize all lists
-  messageDesc.field.filter(isRepeated).forEach((field) => {
-    const value = isMapType(ctx, messageDesc, field) ? '{}' : '[]';
-    const name = maybeSnakeToCamel(field.name, options);
-    chunks.push(code`message.${name} = ${value};`);
-  });
-
   // add a check for each incoming field
   messageDesc.field.forEach((field) => {
     const fieldName = maybeSnakeToCamel(field.name, options);
@@ -1196,6 +1188,9 @@ function generateFromPartial(ctx: Context, fullName: string, messageDesc: Descri
 
     // and then use the snippet to handle repeated fields if necessary
     if (isRepeated(field)) {
+      const value = isMapType(ctx, messageDesc, field) ? '{}' : '[]';
+      const name = maybeSnakeToCamel(field.name, options);
+      chunks.push(code`message.${name} = ${value};`);
       chunks.push(code`if (object.${fieldName} !== undefined && object.${fieldName} !== null) {`);
       if (isMapType(ctx, messageDesc, field)) {
         const i = maybeCastToNumber(ctx, messageDesc, field, 'key');
@@ -1213,6 +1208,7 @@ function generateFromPartial(ctx: Context, fullName: string, messageDesc: Descri
           }
         `);
       }
+      chunks.push(code`}`);
     } else if (isWithinOneOfThatShouldBeUnion(options, field)) {
       let oneofName = maybeSnakeToCamel(messageDesc.oneofDecl[field.oneofIndex].name, options);
       const v = readSnippet(`object.${oneofName}.${fieldName}`);
@@ -1223,25 +1219,33 @@ function generateFromPartial(ctx: Context, fullName: string, messageDesc: Descri
           && object.${oneofName}?.${fieldName} !== null
         ) {
           message.${oneofName} = { $case: '${fieldName}', ${fieldName}: ${v} };
+        }  
       `);
+    } else if ((isLong(field) || isLongValueType(field)) && options.forceLong === LongOption.LONG) {
+      const v = readSnippet(`object.${fieldName}`);
+      const type = basicTypeName(ctx, field);
+      chunks.push(code`if (object.${fieldName} !== undefined && object.${fieldName} !== null) {`);
+      chunks.push(code`message.${fieldName} = ${v} as ${type};`);
+      chunks.push(code`} else {`);
+      const fallback = isWithinOneOf(field) ? 'undefined' : defaultValue(ctx, field);
+      chunks.push(code`message.${fieldName} = ${fallback}`);
+      chunks.push(code`}`);
+    } else if (
+      isPrimitive(field) ||
+      (isTimestamp(field) && (options.useDate === DateOption.DATE || options.useDate === DateOption.STRING)) ||
+      isValueType(ctx, field)
+    ) {
+      // An optimized case of the else below that works when `readSnippet` returns the plain input
+      const fallback = isWithinOneOf(field) ? 'undefined' : defaultValue(ctx, field);
+      chunks.push(code`message.${fieldName} = object.${fieldName} ?? ${fallback};`);
     } else {
       chunks.push(code`if (object.${fieldName} !== undefined && object.${fieldName} !== null) {`);
-      if ((isLong(field) || isLongValueType(field)) && options.forceLong === LongOption.LONG) {
-        const v = readSnippet(`object.${fieldName}`);
-        const type = basicTypeName(ctx, field);
-        chunks.push(code`message.${fieldName} = ${v} as ${type};`);
-      } else {
-        chunks.push(code`message.${fieldName} = ${readSnippet(`object.${fieldName}`)};`);
-      }
-    }
-
-    if (!isRepeated(field) && !isWithinOneOfThatShouldBeUnion(options, field)) {
+      chunks.push(code`message.${fieldName} = ${readSnippet(`object.${fieldName}`)};`);
       chunks.push(code`} else {`);
-      const v = isWithinOneOf(field) ? 'undefined' : defaultValue(ctx, field);
-      chunks.push(code`message.${fieldName} = ${v}`);
+      const fallback = isWithinOneOf(field) ? 'undefined' : defaultValue(ctx, field);
+      chunks.push(code`message.${fieldName} = ${fallback}`);
+      chunks.push(code`}`);
     }
-
-    chunks.push(code`}`);
   });
 
   // and then wrap up the switch/while/return