fix: arrayble is unusable

sindresorhus · Dec 10, 2024 · 42a4ec0 · 42a4ec0
1 parent b24fdd9
commit 42a4ec0
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Showing 2 changed files with 20 additions and 5 deletions.
diff --git a/source/arrayable.d.ts b/source/arrayable.d.ts
@@ -23,4 +23,4 @@ bundle('src/index.js', ['dist/index.cjs', 'dist/index.mjs']);
 
 @category Array
 */
-export type Arrayable<T> = T | readonly T[];
+export type Arrayable<T> = T | T[];
diff --git a/test-d/arrayable.ts b/test-d/arrayable.ts
@@ -3,7 +3,22 @@ import type {Arrayable} from '../index';
 
 declare const unknown: unknown;
 
-expectType<Arrayable<string>>(unknown as string | readonly string[]);
-expectType<Arrayable<string | {foo: number}>>(unknown as (string | {foo: number}) | ReadonlyArray<string | {foo: number}>);
-expectType<Arrayable<never>>(unknown as /* never | */ readonly never[]);
-expectType<Arrayable<string[]>>(unknown as string[] | readonly string[][]);
+expectType<Arrayable<string>>(unknown as string | string[]);
+expectType<Arrayable<string | {foo: number}>>(unknown as (string | {foo: number}) | Array<string | {foo: number}>);
+expectType<Arrayable<never>>(unknown as /* never | */ never[]);
+expectType<Arrayable<string[]>>(unknown as string[] | string[][]);
+
+// Test for issue https://github.com/sindresorhus/type-fest/issues/952
+type Item = number;
+function castArray1(value: Arrayable<Item>): Item[] {
+	return Array.isArray(value) ? value : [value];
+}
+
+expectType<Item[]>(unknown as ReturnType<typeof castArray1>);
+
+function castArray2<T>(value: Arrayable<T>): T[] {
+	return Array.isArray(value) ? value : [value];
+}
+
+expectType<number[]>(castArray2(1));
+expectType<number[]>(castArray2([1, 2, 3]));