diff --git a/integration/grpc-js/simple.ts b/integration/grpc-js/simple.ts
index b8928314b..0f1f16bd5 100644
--- a/integration/grpc-js/simple.ts
+++ b/integration/grpc-js/simple.ts
@@ -85,10 +85,8 @@ 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/simple-long-string/simple.ts b/integration/simple-long-string/simple.ts
index e5b66125f..e62424f93 100644
--- a/integration/simple-long-string/simple.ts
+++ b/integration/simple-long-string/simple.ts
@@ -274,15 +274,11 @@ export const Numbers = {
     {
       message.sfixed64 = object.sfixed64 ?? '0';
     }
-    if (object.guint64 !== undefined && object.guint64 !== null) {
-      message.guint64 = object.guint64;
-    } else {
-      message.guint64 = undefined;
+    {
+      message.guint64 = object.guint64 ?? undefined;
     }
-    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/simple-long/simple.ts b/integration/simple-long/simple.ts
index 1777a8dc8..a75b0be25 100644
--- a/integration/simple-long/simple.ts
+++ b/integration/simple-long/simple.ts
@@ -164,20 +164,14 @@ export const SimpleWithWrappers = {
 
   fromPartial(object: DeepPartial<SimpleWithWrappers>): SimpleWithWrappers {
     const message = { ...baseSimpleWithWrappers } as SimpleWithWrappers;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = undefined;
+    {
+      message.name = object.name ?? undefined;
     }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = undefined;
+    {
+      message.age = object.age ?? undefined;
     }
-    if (object.enabled !== undefined && object.enabled !== null) {
-      message.enabled = object.enabled;
-    } else {
-      message.enabled = undefined;
+    {
+      message.enabled = object.enabled ?? undefined;
     }
     if (object.bananas !== undefined && object.bananas !== null) {
       message.bananas = object.bananas as Long | undefined;
diff --git a/integration/simple-optionals/import_dir/thing.ts b/integration/simple-optionals/import_dir/thing.ts
index 8acd814c2..c0eee8737 100644
--- a/integration/simple-optionals/import_dir/thing.ts
+++ b/integration/simple-optionals/import_dir/thing.ts
@@ -55,10 +55,8 @@ 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 c52244226..fe6844dbf 100644
--- a/integration/simple-optionals/simple.ts
+++ b/integration/simple-optionals/simple.ts
@@ -437,10 +437,8 @@ export const Simple = {
     {
       message.age = object.age ?? 0;
     }
-    if (object.createdAt !== undefined && object.createdAt !== null) {
-      message.createdAt = object.createdAt;
-    } else {
-      message.createdAt = undefined;
+    {
+      message.createdAt = object.createdAt ?? undefined;
     }
     if (object.child !== undefined && object.child !== null) {
       message.child = Child.fromPartial(object.child);
@@ -935,20 +933,14 @@ export const SimpleWithWrappers = {
 
   fromPartial(object: DeepPartial<SimpleWithWrappers>): SimpleWithWrappers {
     const message = { ...baseSimpleWithWrappers } as SimpleWithWrappers;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = undefined;
+    {
+      message.name = object.name ?? undefined;
     }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = undefined;
+    {
+      message.age = object.age ?? undefined;
     }
-    if (object.enabled !== undefined && object.enabled !== null) {
-      message.enabled = object.enabled;
-    } else {
-      message.enabled = undefined;
+    {
+      message.enabled = object.enabled ?? undefined;
     }
     message.coins = [];
     if (object.coins !== undefined && object.coins !== null) {
diff --git a/integration/simple-optionals/thing.ts b/integration/simple-optionals/thing.ts
index 609e9bc3e..2a13db33f 100644
--- a/integration/simple-optionals/thing.ts
+++ b/integration/simple-optionals/thing.ts
@@ -55,10 +55,8 @@ 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-snake/import_dir/thing.ts b/integration/simple-snake/import_dir/thing.ts
index 050b04f5a..9041fa33c 100644
--- a/integration/simple-snake/import_dir/thing.ts
+++ b/integration/simple-snake/import_dir/thing.ts
@@ -55,10 +55,8 @@ 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 276159648..290bdd1c3 100644
--- a/integration/simple-snake/simple.ts
+++ b/integration/simple-snake/simple.ts
@@ -437,10 +437,8 @@ export const Simple = {
     {
       message.age = object.age ?? 0;
     }
-    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;
     }
     if (object.child !== undefined && object.child !== null) {
       message.child = Child.fromPartial(object.child);
@@ -935,20 +933,14 @@ export const SimpleWithWrappers = {
 
   fromPartial(object: DeepPartial<SimpleWithWrappers>): SimpleWithWrappers {
     const message = { ...baseSimpleWithWrappers } as SimpleWithWrappers;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = undefined;
+    {
+      message.name = object.name ?? undefined;
     }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = undefined;
+    {
+      message.age = object.age ?? undefined;
     }
-    if (object.enabled !== undefined && object.enabled !== null) {
-      message.enabled = object.enabled;
-    } else {
-      message.enabled = undefined;
+    {
+      message.enabled = object.enabled ?? undefined;
     }
     message.coins = [];
     if (object.coins !== undefined && object.coins !== null) {
diff --git a/integration/simple-unrecognized-enum/import_dir/thing.ts b/integration/simple-unrecognized-enum/import_dir/thing.ts
index 9c777434d..527ac1a17 100644
--- a/integration/simple-unrecognized-enum/import_dir/thing.ts
+++ b/integration/simple-unrecognized-enum/import_dir/thing.ts
@@ -55,10 +55,8 @@ 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 a602ab9d8..cda6d70a4 100644
--- a/integration/simple-unrecognized-enum/simple.ts
+++ b/integration/simple-unrecognized-enum/simple.ts
@@ -428,10 +428,8 @@ export const Simple = {
     {
       message.age = object.age ?? 0;
     }
-    if (object.createdAt !== undefined && object.createdAt !== null) {
-      message.createdAt = object.createdAt;
-    } else {
-      message.createdAt = undefined;
+    {
+      message.createdAt = object.createdAt ?? undefined;
     }
     if (object.child !== undefined && object.child !== null) {
       message.child = Child.fromPartial(object.child);
@@ -926,20 +924,14 @@ export const SimpleWithWrappers = {
 
   fromPartial(object: DeepPartial<SimpleWithWrappers>): SimpleWithWrappers {
     const message = { ...baseSimpleWithWrappers } as SimpleWithWrappers;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = undefined;
+    {
+      message.name = object.name ?? undefined;
     }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = undefined;
+    {
+      message.age = object.age ?? undefined;
     }
-    if (object.enabled !== undefined && object.enabled !== null) {
-      message.enabled = object.enabled;
-    } else {
-      message.enabled = undefined;
+    {
+      message.enabled = object.enabled ?? undefined;
     }
     message.coins = [];
     if (object.coins !== undefined && object.coins !== null) {
diff --git a/integration/simple/import_dir/thing.ts b/integration/simple/import_dir/thing.ts
index 9c777434d..527ac1a17 100644
--- a/integration/simple/import_dir/thing.ts
+++ b/integration/simple/import_dir/thing.ts
@@ -55,10 +55,8 @@ 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 6f7a5c1fa..e0013c70c 100644
--- a/integration/simple/simple.ts
+++ b/integration/simple/simple.ts
@@ -524,10 +524,8 @@ export const Simple = {
     {
       message.age = object.age ?? 0;
     }
-    if (object.createdAt !== undefined && object.createdAt !== null) {
-      message.createdAt = object.createdAt;
-    } else {
-      message.createdAt = undefined;
+    {
+      message.createdAt = object.createdAt ?? undefined;
     }
     if (object.child !== undefined && object.child !== null) {
       message.child = Child.fromPartial(object.child);
@@ -1048,20 +1046,14 @@ export const SimpleWithWrappers = {
 
   fromPartial(object: DeepPartial<SimpleWithWrappers>): SimpleWithWrappers {
     const message = { ...baseSimpleWithWrappers } as SimpleWithWrappers;
-    if (object.name !== undefined && object.name !== null) {
-      message.name = object.name;
-    } else {
-      message.name = undefined;
+    {
+      message.name = object.name ?? undefined;
     }
-    if (object.age !== undefined && object.age !== null) {
-      message.age = object.age;
-    } else {
-      message.age = undefined;
+    {
+      message.age = object.age ?? undefined;
     }
-    if (object.enabled !== undefined && object.enabled !== null) {
-      message.enabled = object.enabled;
-    } else {
-      message.enabled = undefined;
+    {
+      message.enabled = object.enabled ?? undefined;
     }
     message.coins = [];
     if (object.coins !== undefined && object.coins !== null) {
@@ -1075,10 +1067,8 @@ export const SimpleWithWrappers = {
         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;
   },
@@ -1592,10 +1582,8 @@ export const SimpleWithMap_MapOfTimestampsEntry = {
     {
       message.key = object.key ?? '';
     }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = undefined;
+    {
+      message.value = object.value ?? undefined;
     }
     return message;
   },
@@ -2407,10 +2395,8 @@ export const SimpleButOptional = {
     {
       message.age = object.age ?? undefined;
     }
-    if (object.createdAt !== undefined && object.createdAt !== null) {
-      message.createdAt = object.createdAt;
-    } else {
-      message.createdAt = undefined;
+    {
+      message.createdAt = object.createdAt ?? undefined;
     }
     if (object.child !== undefined && object.child !== null) {
       message.child = Child.fromPartial(object.child);
diff --git a/integration/type-registry/foo.ts b/integration/type-registry/foo.ts
index f54103137..e7400c2a4 100644
--- a/integration/type-registry/foo.ts
+++ b/integration/type-registry/foo.ts
@@ -64,10 +64,8 @@ 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;
   },
@@ -123,10 +121,8 @@ 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/use-date-string/use-date-string.ts b/integration/use-date-string/use-date-string.ts
index 7a7502eb0..dabf8d37e 100644
--- a/integration/use-date-string/use-date-string.ts
+++ b/integration/use-date-string/use-date-string.ts
@@ -131,10 +131,8 @@ export const Todo = {
     {
       message.id = object.id ?? '';
     }
-    if (object.timestamp !== undefined && object.timestamp !== null) {
-      message.timestamp = object.timestamp;
-    } else {
-      message.timestamp = undefined;
+    {
+      message.timestamp = object.timestamp ?? undefined;
     }
     message.repeatedTimestamp = [];
     if (object.repeatedTimestamp !== undefined && object.repeatedTimestamp !== null) {
@@ -142,10 +140,8 @@ export const Todo = {
         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) {
@@ -220,10 +216,8 @@ export const Todo_MapOfTimestampsEntry = {
     {
       message.key = object.key ?? '';
     }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = undefined;
+    {
+      message.value = object.value ?? undefined;
     }
     return message;
   },
diff --git a/integration/use-date-true/use-date-true.ts b/integration/use-date-true/use-date-true.ts
index 4bd0b7db9..4ef512bdd 100644
--- a/integration/use-date-true/use-date-true.ts
+++ b/integration/use-date-true/use-date-true.ts
@@ -131,10 +131,8 @@ export const Todo = {
     {
       message.id = object.id ?? '';
     }
-    if (object.timestamp !== undefined && object.timestamp !== null) {
-      message.timestamp = object.timestamp;
-    } else {
-      message.timestamp = undefined;
+    {
+      message.timestamp = object.timestamp ?? undefined;
     }
     message.repeatedTimestamp = [];
     if (object.repeatedTimestamp !== undefined && object.repeatedTimestamp !== null) {
@@ -142,10 +140,8 @@ export const Todo = {
         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) {
@@ -220,10 +216,8 @@ export const Todo_MapOfTimestampsEntry = {
     {
       message.key = object.key ?? '';
     }
-    if (object.value !== undefined && object.value !== null) {
-      message.value = object.value;
-    } else {
-      message.value = undefined;
+    {
+      message.value = object.value ?? undefined;
     }
     return message;
   },
diff --git a/src/main.ts b/src/main.ts
index c47c1211d..9d7edf548 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -1215,9 +1215,14 @@ function generateFromPartial(ctx: Context, fullName: string, messageDesc: Descri
       chunks.push(code`} else {`);
       const fallback = isWithinOneOf(field) ? 'undefined' : defaultValue(ctx, field);
       chunks.push(code`message.${fieldName} = ${fallback}`);
-    } else if (isPrimitive(field)) {
-      const fallback = isWithinOneOf(field) ? 'undefined' : defaultValue(ctx, field);
+    } else if (
+      isPrimitive(field) ||
+      (isTimestamp(field) && (options.useDate === DateOption.DATE || options.useDate === DateOption.STRING)) ||
+      isValueType(ctx, field)
+    ) {
+      // An optimized case of the else below that works when `readSnippet` returns the plain input
       chunks.push(code`{`); // Without this extra scope the code generation breaks 🤷. We don't really need it.
+      const fallback = isWithinOneOf(field) ? 'undefined' : defaultValue(ctx, field);
       chunks.push(code`message.${fieldName} = object.${fieldName} ?? ${fallback};`);
     } else {
       chunks.push(code`if (object.${fieldName} !== undefined && object.${fieldName} !== null) {`);