Add objectEntries() (#12)

Co-authored-by: Sindre Sorhus <[email protected]>

source/index.ts

@@ -4,3 +4,4 @@ export {isEmpty} from './is-empty.js';
 export {assertError} from './assert-error.js';
 export {asMutable} from './as-mutable.js';
 export {objectKeys} from './object-keys.js';
+export {objectEntries} from './object-entries.js';

source/object-entries.ts

@@ -0,0 +1,21 @@
+/**
+A strongly-typed version of `Object.entries()`.
+
+This is useful since `Object.entries()` always returns an array of `Array<[string, T]>`. This function returns a strongly-typed array of the entries of the given object.
+
+- [TypeScript issues about this](https://github.com/microsoft/TypeScript/pull/12253)
+
+@example
+```
+import {objectEntries} from 'ts-extras';
+
+const stronglyTypedEntries = objectEntries({a: 1, b: 2, c: 3});
+//=> Array<['a' | 'b' | 'c', number]>
+
+const untypedEntries = Object.entries(items);
+//=> Array<[string, number]>
+```
+*/
+export function objectEntries<Type extends Record<PropertyKey, unknown>, Key extends `${Exclude<keyof Type, symbol>}`>(value: Type): Array<[Key, Type[Key]]> {
+	return Object.entries(value) as Array<[Key, Type[Key]]>;
+}

test/object-entries.ts

@@ -0,0 +1,15 @@
+import test from 'ava';
+import {expectTypeOf} from 'expect-type';
+import {objectEntries} from '../source/index.js';
+
+test('objectEntries()', t => {
+	type Entry = ['1' | 'stringKey', number | string];
+	const entries = objectEntries({
+		1: 123,
+		stringKey: 'someString',
+		[Symbol('symbolKey')]: true,
+	});
+
+	expectTypeOf<Entry[]>(entries);
+	t.deepEqual(entries, [['1', 123], ['stringKey', 'someString']]);
+});