type-fest - npm Package Compare versions

Comparing version 4.9.0 to 4.10.0

package.json

 {
 	"name": "type-fest",
-	"version": "4.9.0",
+	"version": "4.10.0",
 	"description": "A collection of essential TypeScript types",
@@ -5,0 +5,0 @@ "license": "(MIT OR CC0-1.0)",

source/delimiter-cased-properties-deep.d.ts

 import type {DelimiterCase} from './delimiter-case';
+import type {NonRecursiveType} from './internal';
 import type {UnknownArray} from './unknown-array';
@@ -51,3 +52,3 @@
 	Delimiter extends string,
-> = Value extends Function | Date | RegExp
+> = Value extends NonRecursiveType
 	? Value
@@ -54,0 +55,0 @@ : Value extends UnknownArray

source/get.d.ts

@@ -20,3 +20,3 @@ import type {StringDigit} from '../source/internal';
 type GetWithPath<BaseType, Keys extends readonly string[], Options extends GetOptions = {}> =
-	Keys extends []
+	Keys extends readonly []
 		? BaseType
@@ -129,3 +129,3 @@ : Keys extends readonly [infer Head, ...infer Tail]
 			? StrictPropertyOf<BaseType, Key, Options>
-			: BaseType extends [] | [unknown, ...unknown[]]
+			: BaseType extends readonly [] | readonly [unknown, ...unknown[]]
 				? unknown // It's a tuple, but `Key` did not extend `keyof BaseType`. So the index is out of bounds.
@@ -132,0 +132,0 @@ : BaseType extends {

source/internal.d.ts

@@ -439,1 +439,36 @@ import type {Primitive} from './primitive';
 			: InternalUnionMax<N, [...T, unknown]>;
+
+/**
+Returns a boolean for whether the given type is a union type.
+
+@example
+```
+type A = IsUnion<string | number>;
+//=> true
+
+type B = IsUnion<string>;
+//=> false
+```
+*/
+export type IsUnion<T> = InternalIsUnion<T>;
+
+/**
+The actual implementation of `IsUnion`.
+*/
+type InternalIsUnion<T, U = T> =
+(
+	// @link https://ghaiklor.github.io/type-challenges-solutions/en/medium-isunion.html
+	IsNever<T> extends true
+		? false
+		: T extends any
+			? [U] extends [T]
+				? false
+				: true
+			: never
+) extends infer Result
+	// In some cases `Result` will return `false | true` which is `boolean`,
+	// that means `T` has at least two types and it's a union type,
+	// so we will return `true` instead of `boolean`.
+	? boolean extends Result ? true
+		: Result
+	: never; // Should never happen

source/merge.d.ts

 import type {OmitIndexSignature} from './omit-index-signature';
 import type {PickIndexSignature} from './pick-index-signature';
-import type {EnforceOptional} from './enforce-optional';
+import type {Simplify} from './simplify';
 
@@ -44,4 +44,6 @@ // Merges two objects without worrying about index signatures.
 */
-export type Merge<Destination, Source> = EnforceOptional<
+export type Merge<Destination, Source> =
+Simplify<
 SimpleMerge<PickIndexSignature<Destination>, PickIndexSignature<Source>>
-& SimpleMerge<OmitIndexSignature<Destination>, OmitIndexSignature<Source>>>;
+& SimpleMerge<OmitIndexSignature<Destination>, OmitIndexSignature<Source>>
+>;

source/shared-union-fields-deep.d.ts

@@ -1,2 +0,2 @@
-import type {NonRecursiveType, UnionMin, UnionMax, TupleLength, StaticPartOfArray, VariablePartOfArray} from './internal';
+import type {NonRecursiveType, UnionMin, UnionMax, TupleLength, StaticPartOfArray, VariablePartOfArray, IsUnion} from './internal';
 import type {IsNever} from './is-never';
@@ -111,6 +111,9 @@ import type {UnknownArray} from './unknown-array';
 export type SharedUnionFieldsDeep<Union, Options extends SharedUnionFieldsDeepOptions = {recurseIntoArrays: false}> =
+// If `Union` is not a union type, return `Union` directly.
+IsUnion<Union> extends false
+	? Union
 	// `Union extends` will convert `Union`
 	// to a [distributive conditionaltype](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-8.html#distributive-conditional-types).
 	// But this is not what we want, so we need to wrap `Union` with `[]` to prevent it.
-	[Union] extends [NonRecursiveType | ReadonlyMap<unknown, unknown> | ReadonlySet<unknown>]
+	: [Union] extends [NonRecursiveType | ReadonlyMap<unknown, unknown> | ReadonlySet<unknown>]
 		? Union
@@ -117,0 +120,0 @@ : [Union] extends [UnknownArray]

No alert changes

Improved metrics

Total package byte prevSize

319807

increased by0.3%

Lines of code

7512

increased by0.49%

No dependency changes