Add NonNull

README.md

@@ -99,6 +99,7 @@ We are open for contributions. If you're planning to contribute please make sure
 * [`Extract<A, B>`](#extracta-b) _(built-in)_
 * [`NonNullable<T>`](#nonnullablea) _(built-in)_
 * [`NonUndefined<T>`](#nonundefineda)
+* [`NonNull<T>`](#nonnulla)
 
 ## Object operators
 
@@ -281,6 +282,12 @@ Exclude `undefined` from set `A`
 
 [⇧ back to top](#table-of-contents)
 
+### `NonNull<A>`
+
+Exclude `null` from set `A`
+
+[⇧ back to top](#table-of-contents)
+
 ### `Exclude<A, B>`
 
 Exclude subset `B` from set `A`

src/__snapshots__/mapped-types.spec.ts.snap

@@ -127,6 +127,10 @@ exports[`MutableKeys testType<MutableKeys<ReadWriteProps>>() (type) should match
 
 exports[`NonFunctionKeys testType<NonFunctionKeys<MixedProps>>() (type) should match snapshot 1`] = `"\\"name\\" | \\"someKeys\\""`;
 
+exports[`NonNull testType<NonNull<null>>() (type) should match snapshot 1`] = `"never"`;
+
+exports[`NonNull testType<NonNull<string | null | undefined>>() (type) should match snapshot 1`] = `"string | undefined"`;
+
 exports[`NonUndefined testType<NonUndefined<string | null | undefined>>() (type) should match snapshot 1`] = `"string | null"`;
 
 exports[`NonUndefined testType<NonUndefined<undefined>>() (type) should match snapshot 1`] = `"never"`;

src/mapped-types.spec.snap.ts

@@ -6,6 +6,7 @@ import {
   SymmetricDifference,
   FunctionKeys,
   NonUndefined,
+  NonNull,
   NonFunctionKeys,
   Omit,
   PickByValue,
@@ -104,6 +105,14 @@ type RequiredOptionalProps = {
   testType<NonUndefined<undefined>>();
 }
 
+// @dts-jest:group NonNull
+{
+  // @dts-jest:pass:snap -> string | undefined
+  testType<NonNull<string | null | undefined>>();
+  // @dts-jest:pass:snap -> never
+  testType<NonNull<null>>();
+}
+
 // @dts-jest:group FunctionKeys
 {
   // @dts-jest:pass:snap -> "setName" | "someFn"

src/mapped-types.spec.ts

@@ -6,6 +6,7 @@ import {
   SymmetricDifference,
   FunctionKeys,
   NonUndefined,
+  NonNull,
   NonFunctionKeys,
   Omit,
   PickByValue,
@@ -104,6 +105,14 @@ type RequiredOptionalProps = {
   testType<NonUndefined<undefined>>();
 }
 
+// @dts-jest:group NonNull
+{
+  // @dts-jest:pass:snap
+  testType<NonNull<string | null | undefined>>();
+  // @dts-jest:pass:snap
+  testType<NonNull<null>>();
+}
+
 // @dts-jest:group FunctionKeys
 {
   // @dts-jest:pass:snap

src/mapped-types.ts

@@ -52,16 +52,25 @@ export type SymmetricDifference<A, B> = SetDifference<A | B, A & B>;
  * @desc Exclude undefined from set `A`
  * @example
  *   // Expect: "string | null"
- *   SymmetricDifference<string | null | undefined>;
+ *   NonUndefined<string | null | undefined>;
  */
-export type NonUndefined<A> = A extends undefined ? never : A;
+export type NonUndefined<A> = Exclude<A, undefined>;
+
+/**
+ * NonUndefined
+ * @desc Exclude undefined from set `A`
+ * @example
+ *   // Expect: "string | undefined"
+ *   NonNull<string | null | undefined>;
+ */
+export type NonNull<A> = Exclude<A, null>;
 
 /**
  * NonNullable
  * @desc Exclude undefined and null from set `A`
  * @example
  *   // Expect: "string"
- *   SymmetricDifference<string | null | undefined>;
+ *   NonNullable<string | null | undefined>;
  */
 // type NonNullable - built-in