Add NonNull

piotrwitek · Mar 28, 2020 · 8dd7b16 · 8dd7b16
1 parent ba66c89
commit 8dd7b16
Show file tree

Hide file tree

Showing 5 changed files with 41 additions and 3 deletions.
diff --git a/README.md b/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`

diff --git a/src/__snapshots__/mapped-types.spec.ts.snap b/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"`;

diff --git a/src/mapped-types.spec.snap.ts b/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"

diff --git a/src/mapped-types.spec.ts b/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

diff --git a/src/mapped-types.ts b/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