Require ESM and Node.js 20

Author: sindresorhus

.github/workflows/main.yml

@@ -16,9 +16,9 @@ jobs:
       fail-fast: false
       matrix:
         node-version:
+          - 24
           - 22
           - 20
-          - 18
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
@@ -33,20 +33,13 @@ jobs:
       fail-fast: false
       matrix:
         typescript-version:
-          - "latest"
-          - "~5.8.0"
-          - "~5.7.0"
-          - "~5.6.0"
-          - "~5.5.0"
-          - "~5.4.0"
-          - "~5.3.0"
-          - "~5.2.0"
-          - "~5.1.0"
+          - 'latest'
+          - '~5.8.0'
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 18
+          node-version: 20
       - run: npm install
       - run: npm install typescript@${{ matrix.typescript-version }}
       - run: npx tsc

index.d.ts

@@ -10,10 +10,14 @@
 		"email": "[email protected]",
 		"url": "https://sindresorhus.com"
 	},
+	"type": "module",
+	"exports": {
+		"types": "./index.d.ts"
+	},
 	"types": "./index.d.ts",
 	"sideEffects": false,
 	"engines": {
-		"node": ">=16"
+		"node": ">=20"
 	},
 	"scripts": {
 		"test:source-files-extension": "node script/test/source-files-extension.js",
@@ -41,8 +45,9 @@
 		"generics"
 	],
 	"devDependencies": {
-		"expect-type": "^1.1.0",
-		"npm-run-all2": "^7.0.1",
+		"@sindresorhus/tsconfig": "^7.0.0",
+		"expect-type": "^1.2.1",
+		"npm-run-all2": "^8.0.1",
 		"tsd": "^0.32.0",
 		"typescript": "~5.8.3",
 		"xo": "^0.60.0"
@@ -53,7 +58,6 @@
 			"@typescript-eslint/ban-ts-comment": "off",
 			"@typescript-eslint/ban-types": "off",
 			"@typescript-eslint/naming-convention": "off",
-			"import/extensions": "off",
 			"@typescript-eslint/no-redeclare": "off",
 			"@typescript-eslint/no-confusing-void-expression": "off",
 			"@typescript-eslint/no-unsafe-argument": "off",

package.json

@@ -83,7 +83,10 @@ PR welcome for additional commonly needed types and docs improvements. Read the
 npm install type-fest
 ```
 
-*Requires TypeScript >=5.1 and [`{strict: true}`](https://www.typescriptlang.org/tsconfig#strict) in your tsconfig.*
+*Requires TypeScript >=5.8, [ESM](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c), and [`{strict: true}`](https://www.typescriptlang.org/tsconfig#strict) in your tsconfig.*
+
+> [!NOTE]
+> This readme shows the current development version. For docs about the latest version, see the [npm page](https://www.npmjs.com/package/type-fest).
 
 ## Usage
 

readme.md

@@ -1,6 +1,5 @@
-/* eslint-disable unicorn/prefer-module */
-const fs = require('node:fs');
-const process = require('node:process');
+import fs from 'node:fs';
+import process from 'node:process';
 
 const checkSourceFilesExtension = async () => {
 	try {

script/test/source-files-extension.js

@@ -1,8 +1,8 @@
-import type {NonRecursiveType, ReadonlyKeysOfUnion, ValueOfUnion} from './internal';
-import type {KeysOfUnion} from './keys-of-union';
-import type {SharedUnionFields} from './shared-union-fields';
-import type {Simplify} from './simplify';
-import type {UnknownArray} from './unknown-array';
+import type {NonRecursiveType, ReadonlyKeysOfUnion, ValueOfUnion} from './internal/index.d.ts';
+import type {KeysOfUnion} from './keys-of-union.d.ts';
+import type {SharedUnionFields} from './shared-union-fields.d.ts';
+import type {Simplify} from './simplify.d.ts';
+import type {UnknownArray} from './unknown-array.d.ts';
 
 /**
 Create a type with all fields from a union of object types.

source/all-union-fields.d.ts

@@ -1,4 +1,4 @@
-import type {IsEqual} from './is-equal';
+import type {IsEqual} from './is-equal.d.ts';
 
 /**
 Returns a boolean for whether two given types are both true.

source/and.d.ts

@@ -1,12 +1,12 @@
-import type {Sum} from './sum';
-import type {LessThanOrEqual} from './less-than-or-equal';
-import type {GreaterThanOrEqual} from './greater-than-or-equal';
-import type {GreaterThan} from './greater-than';
-import type {IsNegative} from './numeric';
-import type {Not, TupleMin} from './internal';
-import type {IsEqual} from './is-equal';
-import type {And} from './and';
-import type {ArraySplice} from './array-splice';
+import type {Sum} from './sum.d.ts';
+import type {LessThanOrEqual} from './less-than-or-equal.d.ts';
+import type {GreaterThanOrEqual} from './greater-than-or-equal.d.ts';
+import type {GreaterThan} from './greater-than.d.ts';
+import type {IsNegative} from './numeric.d.ts';
+import type {Not, TupleMin} from './internal/index.d.ts';
+import type {IsEqual} from './is-equal.d.ts';
+import type {And} from './and.d.ts';
+import type {ArraySplice} from './array-splice.d.ts';
 
 /**
 Returns an array slice of a given range, just like `Array#slice()`.

source/array-slice.d.ts

@@ -1,7 +1,7 @@
-import type {BuildTuple, StaticPartOfArray, VariablePartOfArray} from './internal';
-import type {GreaterThanOrEqual} from './greater-than-or-equal';
-import type {Subtract} from './subtract';
-import type {UnknownArray} from './unknown-array';
+import type {BuildTuple, StaticPartOfArray, VariablePartOfArray} from './internal/index.d.ts';
+import type {GreaterThanOrEqual} from './greater-than-or-equal.d.ts';
+import type {Subtract} from './subtract.d.ts';
+import type {UnknownArray} from './unknown-array.d.ts';
 
 /**
 The implementation of `SplitArrayByIndex` for fixed length arrays.

source/array-splice.d.ts

@@ -1,5 +1,5 @@
-import type {ApplyDefaultOptions, IfArrayReadonly} from './internal';
-import type {UnknownArray} from './unknown-array';
+import type {ApplyDefaultOptions, IfArrayReadonly} from './internal/index.d.ts';
+import type {UnknownArray} from './unknown-array.d.ts';
 
 /**
 @see {@link ArrayTail}