Require Node.js 18

.gitignore

@@ -1,4 +1,4 @@
 node_modules
 yarn.lock
-dist
+/distribution
 .tsimp

package.json

@@ -11,19 +11,21 @@
 		"url": "https://sindresorhus.com"
 	},
 	"type": "module",
-	"exports": "./dist/index.js",
-	"types": "./dist/index.d.ts",
+	"exports": {
+		"types": "./distribution/index.d.ts",
+		"default": "./distribution/index.js"
+	},
 	"sideEffects": false,
 	"engines": {
-		"node": ">=16"
+		"node": ">=18"
 	},
 	"scripts": {
-		"build": "del dist && tsc",
+		"build": "del distribution && tsc",
 		"test": "tsc --noEmit && xo && ava",
 		"prepare": "npm run build"
 	},
 	"files": [
-		"dist"
+		"distribution"
 	],
 	"keywords": [
 		"type",
@@ -50,19 +52,19 @@
 		"types"
 	],
 	"devDependencies": {
-		"@sindresorhus/tsconfig": "^5.0.0",
+		"@sindresorhus/tsconfig": "^6.0.0",
 		"@types/jsdom": "^21.1.7",
-		"@types/node": "^20.14.8",
-		"@types/zen-observable": "^0.8.3",
+		"@types/node": "^20.14.10",
+		"@types/zen-observable": "^0.8.7",
 		"ava": "^6.1.3",
-		"del-cli": "^5.0.0",
-		"expect-type": "^0.16.0",
-		"jsdom": "^22.1.0",
+		"del-cli": "^5.1.0",
+		"expect-type": "^0.19.0",
+		"jsdom": "^24.1.0",
 		"rxjs": "^7.8.1",
 		"tempy": "^3.1.0",
 		"tsimp": "^2.0.11",
-		"typescript": "^5.1.6",
-		"xo": "^0.56.0",
+		"typescript": "^5.5.3",
+		"xo": "^0.58.0",
 		"zen-observable": "^0.10.0"
 	},
 	"ava": {

readme.md

@@ -133,6 +133,10 @@ is.array(value, is.number); // Validate `value` is an array and all of its items
 ##### .function(value)
 
 ##### .buffer(value)
+
+> [!NOTE]
+> [Prefer using `Uint8Array` instead of `Buffer`.](https://sindresorhus.com/blog/goodbye-nodejs-buffer)
+
 ##### .blob(value)
 ##### .object(value)
 

source/index.ts

@@ -1,4 +1,3 @@
-import type {Buffer} from 'node:buffer';
 import type {
 	ArrayLike,
 	Class,
@@ -13,6 +12,14 @@ import type {
 	Whitespace,
 } from './types.js';
 
+// From type-fest.
+type ExtractFromGlobalConstructors<Name extends string> =
+	Name extends string
+		? typeof globalThis extends Record<Name, new (...arguments_: any[]) => infer T> ? T : never
+		: never;
+
+type NodeBuffer = ExtractFromGlobalConstructors<'Buffer'>;
+
 const typedArrayTypeNames = [
 	'Int8Array',
 	'Uint8Array',
@@ -314,7 +321,7 @@ const is = Object.assign(
 	},
 );
 
-function isAbsoluteMod2(remainder: 0 | 1) {
+function isAbsoluteModule2(remainder: 0 | 1) {
 	return (value: unknown): value is number => isInteger(value) && Math.abs(value % 2) === remainder;
 }
 
@@ -350,15 +357,15 @@ export function isArrayLike<T = unknown>(value: unknown): value is ArrayLike<T>
 	return !isNullOrUndefined(value) && !isFunction(value) && isValidLength((value as ArrayLike<T>).length);
 }
 
-export function isAsyncFunction<T = unknown>(value: unknown): value is ((...args: any[]) => Promise<T>) {
+export function isAsyncFunction<T = unknown>(value: unknown): value is ((...arguments_: any[]) => Promise<T>) {
 	return getObjectType(value) === 'AsyncFunction';
 }
 
 export function isAsyncGenerator(value: unknown): value is AsyncGenerator {
 	return isAsyncIterable(value) && isFunction((value as AsyncGenerator).next) && isFunction((value as AsyncGenerator).throw);
 }
 
-export function isAsyncGeneratorFunction(value: unknown): value is ((...args: any[]) => Promise<unknown>) {
+export function isAsyncGeneratorFunction(value: unknown): value is ((...arguments_: any[]) => Promise<unknown>) {
 	return getObjectType(value) === 'AsyncGeneratorFunction';
 }
 
@@ -388,10 +395,13 @@ export function isBoolean(value: unknown): value is boolean {
 
 // eslint-disable-next-line @typescript-eslint/ban-types
 export function isBoundFunction(value: unknown): value is Function {
-	return isFunction(value) && !Object.prototype.hasOwnProperty.call(value, 'prototype');
+	return isFunction(value) && !Object.hasOwn(value, 'prototype');
 }
 
-export function isBuffer(value: unknown): value is Buffer {
+/**
+Note: [Prefer using `Uint8Array` instead of `Buffer`.](https://sindresorhus.com/blog/goodbye-nodejs-buffer)
+*/
+export function isBuffer(value: unknown): value is NodeBuffer {
 	// eslint-disable-next-line @typescript-eslint/no-unsafe-return, @typescript-eslint/no-unsafe-call
 	return (value as any)?.constructor?.isBuffer?.(value) ?? false;
 }
@@ -450,7 +460,7 @@ export function isError(value: unknown): value is Error {
 }
 
 export function isEvenInteger(value: unknown): value is number {
-	return isAbsoluteMod2(0)(value);
+	return isAbsoluteModule2(0)(value);
 }
 
 // Example: `is.falsy = (value: unknown): value is (not true | 0 | '' | undefined | null) => Boolean(value);`
@@ -629,7 +639,7 @@ export function isObservable(value: unknown): value is ObservableLike {
 }
 
 export function isOddInteger(value: unknown): value is number {
-	return isAbsoluteMod2(1)(value);
+	return isAbsoluteModule2(1)(value);
 }
 
 export function isPlainObject<Value = unknown>(value: unknown): value is Record<PropertyKey, Value> {
@@ -768,7 +778,7 @@ export function isWeakMap<Key extends object = object, Value = unknown>(value: u
 	return getObjectType(value) === 'WeakMap';
 }
 
-// eslint-disable-next-line @typescript-eslint/ban-types
+// eslint-disable-next-line @typescript-eslint/ban-types, unicorn/prevent-abbreviations
 export function isWeakRef(value: unknown): value is WeakRef<object> {
 	return getObjectType(value) === 'WeakRef';
 }
@@ -782,7 +792,7 @@ export function isWhitespaceString(value: unknown): value is Whitespace {
 	return isString(value) && /^\s+$/.test(value);
 }
 
-type ArrayMethod = (fn: (value: unknown, index: number, array: unknown[]) => boolean, thisArg?: unknown) => boolean;
+type ArrayMethod = (function_: (value: unknown, index: number, array: unknown[]) => boolean, thisArgument?: unknown) => boolean;
 
 function predicateOnArray(method: ArrayMethod, predicate: Predicate, values: unknown[]) {
 	if (!isFunction(predicate)) {
@@ -832,7 +842,7 @@ type Assert = {
 	symbol: (value: unknown, message?: string) => asserts value is symbol;
 	numericString: (value: unknown, message?: string) => asserts value is `${number}`;
 	array: <T = unknown>(value: unknown, assertion?: (element: unknown) => asserts element is T, message?: string) => asserts value is T[];
-	buffer: (value: unknown, message?: string) => asserts value is Buffer;
+	buffer: (value: unknown, message?: string) => asserts value is NodeBuffer;
 	blob: (value: unknown, message?: string) => asserts value is Blob;
 	// eslint-disable-next-line @typescript-eslint/ban-types
 	nullOrUndefined: (value: unknown, message?: string) => asserts value is null | undefined;
@@ -1218,7 +1228,10 @@ export function assertBoundFunction(value: unknown, message?: string): asserts v
 	}
 }
 
-export function assertBuffer(value: unknown, message?: string): asserts value is Buffer {
+/**
+Note: [Prefer using `Uint8Array` instead of `Buffer`.](https://sindresorhus.com/blog/goodbye-nodejs-buffer)
+*/
+export function assertBuffer(value: unknown, message?: string): asserts value is NodeBuffer {
 	if (!isBuffer(value)) {
 		throw new TypeError(message ?? typeErrorMessage('Buffer', value));
 	}
@@ -1656,7 +1669,7 @@ export function assertWeakMap<Key extends object = object, Value = unknown>(valu
 	}
 }
 
-// eslint-disable-next-line @typescript-eslint/ban-types
+// eslint-disable-next-line @typescript-eslint/ban-types, unicorn/prevent-abbreviations
 export function assertWeakRef<T extends object = object>(value: unknown, message?: string): asserts value is WeakRef<T> {
 	if (!isWeakRef(value)) {
 		throw new TypeError(message ?? typeErrorMessage('WeakRef', value));

source/types.ts

@@ -56,7 +56,7 @@ export type ObservableLike = {
 // eslint-disable-next-line @typescript-eslint/ban-types
 export type Falsy = false | 0 | 0n | '' | null | undefined;
 
-export type WeakRef<T extends object> = { // eslint-disable-line @typescript-eslint/ban-types
+export type WeakRef<T extends object> = { // eslint-disable-line @typescript-eslint/ban-types, unicorn/prevent-abbreviations
 	readonly [Symbol.toStringTag]: 'WeakRef';
 	deref(): T | undefined;
 };

test/test.ts

@@ -27,18 +27,18 @@ const {document} = window;
 const structuredClone = globalThis.structuredClone ?? (x => x);
 
 type Test = {
-	assert: (...args: any[]) => void | never;
+	assert: (...arguments_: any[]) => void | never;
 	fixtures: unknown[];
 	typename?: TypeName;
 	typeDescription?: AssertionTypeDescription;
 	is(value: unknown): boolean;
 };
 
-const invertAssertThrow = (description: AssertionTypeDescription, fn: () => void | never, value: unknown): void | never => {
+const invertAssertThrow = (description: AssertionTypeDescription, function_: () => void | never, value: unknown): void | never => {
 	const expectedAssertErrorMessage = `Expected value which is \`${description}\`, received value of type \`${is(value)}\`.`;
 
 	try {
-		fn();
+		function_();
 	} catch (error: unknown) {
 		if (error instanceof TypeError && error.message.includes(expectedAssertErrorMessage)) {
 			return;
@@ -488,10 +488,10 @@ const types = new Map<string, Test>([
 		fixtures: [
 			{x: 1},
 			Object.create(null),
-			new Object(), // eslint-disable-line no-new-object
+			new Object(), // eslint-disable-line no-object-constructor
 			structuredClone({x: 1}),
 			structuredClone(Object.create(null)),
-			structuredClone(new Object()), // eslint-disable-line no-new-object
+			structuredClone(new Object()), // eslint-disable-line no-object-constructor
 		],
 		typename: 'Object',
 		typeDescription: 'plain object',
@@ -1841,14 +1841,14 @@ test('is.nonEmptyStringAndNotWhitespace', t => {
 
 test('is.emptyObject', t => {
 	t.true(is.emptyObject({}));
-	t.true(is.emptyObject(new Object())); // eslint-disable-line no-new-object
+	t.true(is.emptyObject(new Object())); // eslint-disable-line no-object-constructor
 	t.false(is.emptyObject({unicorn: '🦄'}));
 
 	t.notThrows(() => {
 		assert.emptyObject({});
 	});
 	t.notThrows(() => {
-		assert.emptyObject(new Object()); // eslint-disable-line no-new-object
+		assert.emptyObject(new Object()); // eslint-disable-line no-object-constructor
 	});
 	t.throws(() => {
 		assert.emptyObject({unicorn: '🦄'});
@@ -1860,14 +1860,14 @@ test('is.nonEmptyObject', t => {
 	is.nonEmptyObject(foo);
 
 	t.false(is.nonEmptyObject({}));
-	t.false(is.nonEmptyObject(new Object())); // eslint-disable-line no-new-object
+	t.false(is.nonEmptyObject(new Object())); // eslint-disable-line no-object-constructor
 	t.true(is.nonEmptyObject({unicorn: '🦄'}));
 
 	t.throws(() => {
 		assert.nonEmptyObject({});
 	});
 	t.throws(() => {
-		assert.nonEmptyObject(new Object()); // eslint-disable-line no-new-object
+		assert.nonEmptyObject(new Object()); // eslint-disable-line no-object-constructor
 	});
 	t.notThrows(() => {
 		assert.nonEmptyObject({unicorn: '🦄'});

tsconfig.json

@@ -1,8 +1,5 @@
 {
 	"extends": "@sindresorhus/tsconfig",
-	"compilerOptions": {
-		"outDir": "dist",
-	},
 	"include": [
 		"source"
 	],