Require Node.js 14, TS 4.7, and move to ESM (#167)

.github/workflows/main.yml

@@ -10,12 +10,12 @@ jobs:
       fail-fast: false
       matrix:
         node-version:
+          - 18
+          - 16
           - 14
-          - 12
-          - 10
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-node@v1
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
         with:
           node-version: ${{ matrix.node-version }}
       - run: npm install

package.json

@@ -10,9 +10,11 @@
 		"email": "sindresorhus@gmail.com",
 		"url": "https://sindresorhus.com"
 	},
-	"main": "dist/index.js",
+	"type": "module",
+	"exports": "./index.js",
+	"types": "./index.d.ts",
 	"engines": {
-		"node": ">=10"
+		"node": ">=14.16"
 	},
 	"scripts": {
 		"build": "del dist && tsc",
@@ -47,50 +49,34 @@
 		"types"
 	],
 	"devDependencies": {
-		"@sindresorhus/tsconfig": "^0.7.0",
-		"@types/jsdom": "^16.1.0",
-		"@types/node": "^14.0.13",
-		"@types/zen-observable": "^0.8.0",
-		"@typescript-eslint/eslint-plugin": "^2.20.0",
-		"@typescript-eslint/parser": "^2.20.0",
-		"ava": "^3.3.0",
-		"del-cli": "^2.0.0",
-		"eslint-config-xo-typescript": "^0.26.0",
-		"jsdom": "^16.0.1",
-		"rxjs": "^6.4.0",
-		"tempy": "^0.4.0",
-		"ts-node": "^8.3.0",
-		"typescript": "~3.8.2",
-		"xo": "^0.26.1",
-		"zen-observable": "^0.8.8"
+		"@sindresorhus/tsconfig": "^3.0.1",
+		"@types/jsdom": "^16.2.14",
+		"@types/node": "^17.0.42",
+		"@types/zen-observable": "^0.8.3",
+		"ava": "^4.3.0",
+		"del-cli": "^4.0.1",
+		"jsdom": "^19.0.0",
+		"rxjs": "^7.5.5",
+		"tempy": "^3.0.0",
+		"ts-node": "^10.8.1",
+		"typescript": "~4.7.3",
+		"xo": "^0.50.0",
+		"zen-observable": "^0.8.15"
 	},
-	"types": "dist/index.d.ts",
 	"sideEffects": false,
 	"ava": {
-		"extensions": [
-			"ts"
-		],
-		"require": [
-			"ts-node/register"
+		"extensions": {
+			"ts": "module"
+		},
+		"nodeArguments": [
+			"--loader=ts-node/esm"
 		]
 	},
 	"xo": {
-		"extends": "xo-typescript",
-		"extensions": [
-			"ts"
-		],
-		"parserOptions": {
-			"project": "./tsconfig.xo.json"
-		},
-		"globals": [
-			"BigInt",
-			"BigInt64Array",
-			"BigUint64Array"
-		],
 		"rules": {
-			"@typescript-eslint/promise-function-async": "off",
 			"@typescript-eslint/no-empty-function": "off",
-			"@typescript-eslint/explicit-function-return-type": "off"
+			"@typescript-eslint/explicit-function-return-type": "off",
+			"@typescript-eslint/triple-slash-reference": "off"
 		}
 	}
 }

readme.md

@@ -24,7 +24,7 @@ npm install @sindresorhus/is
 ## Usage
 
 ```js
-const is = require('@sindresorhus/is');
+import is from '@sindresorhus/is';
 
 is('🦄');
 //=> 'string'
@@ -39,7 +39,7 @@ is.number(6);
 [Assertions](#type-assertions) perform the same type checks, but throw an error if the type does not match.
 
 ```js
-const {assert} = require('@sindresorhus/is');
+import {assert} from '@sindresorhus/is';
 
 assert.string(2);
 //=> Error: Expected value which is `string`, received value of type `number`.
@@ -436,7 +436,7 @@ Returns `true` if `value` is a DOM Element.
 Returns `true` if `value` is a Node.js [stream](https://nodejs.org/api/stream.html).
 
 ```js
-const fs = require('fs');
+import fs from 'node:fs';
 
 is.nodeStream(fs.createReadStream('unicorn.png'));
 //=> true
@@ -447,7 +447,7 @@ is.nodeStream(fs.createReadStream('unicorn.png'));
 Returns `true` if `value` is an `Observable`.
 
 ```js
-const {Observable} = require('rxjs');
+import {Observable} from 'rxjs';
 
 is.observable(new Observable());
 //=> true

source/index.ts

@@ -1,8 +1,5 @@
-/// <reference lib="es2018"/>
-/// <reference lib="dom"/>
-/// <reference types="node"/>
-
-import {Class, Falsy, TypedArray, ObservableLike, Primitive} from './types';
+import type {Buffer} from 'node:buffer';
+import type {Class, Falsy, TypedArray, ObservableLike, Primitive} from './types.js';
 
 const typedArrayTypeNames = [
 	'Int8Array',
@@ -15,7 +12,7 @@ const typedArrayTypeNames = [
 	'Float32Array',
 	'Float64Array',
 	'BigInt64Array',
-	'BigUint64Array'
+	'BigUint64Array',
 ] as const;
 
 type TypedArrayTypeName = typeof typedArrayTypeNames[number];
@@ -52,7 +49,7 @@ const objectTypeNames = [
 	'URLSearchParams',
 	'HTMLElement',
 	'NaN',
-	...typedArrayTypeNames
+	...typedArrayTypeNames,
 ] as const;
 
 type ObjectTypeName = typeof objectTypeNames[number];
@@ -68,7 +65,7 @@ const primitiveTypeNames = [
 	'number',
 	'bigint',
 	'boolean',
-	'symbol'
+	'symbol',
 ] as const;
 
 type PrimitiveTypeName = typeof primitiveTypeNames[number];
@@ -149,6 +146,7 @@ function is(value: unknown): TypeName {
 }
 
 is.undefined = isOfType<undefined>('undefined');
+
 is.string = isOfType<string>('string');
 
 const isNumberType = isOfType<number>('number');
@@ -159,9 +157,13 @@ is.bigint = isOfType<bigint>('bigint');
 // eslint-disable-next-line @typescript-eslint/ban-types
 is.function_ = isOfType<Function>('function');
 
+// eslint-disable-next-line @typescript-eslint/ban-types
 is.null_ = (value: unknown): value is null => value === null;
+
 is.class_ = (value: unknown): value is Class => is.function_(value) && value.toString().startsWith('class ');
+
 is.boolean = (value: unknown): value is boolean => value === true || value === false;
+
 is.symbol = isOfType<symbol>('symbol');
 
 is.numericString = (value: unknown): value is string =>
@@ -176,14 +178,18 @@ is.array = <T = unknown>(value: unknown, assertion?: (value: T) => value is T):
 		return true;
 	}
 
-	return value.every(assertion);
+	return value.every(element => assertion(element));
 };
 
+// eslint-disable-next-line @typescript-eslint/no-unsafe-return, @typescript-eslint/no-unsafe-call
 is.buffer = (value: unknown): value is Buffer => (value as any)?.constructor?.isBuffer?.(value) ?? false;
+
 is.blob = (value: unknown): value is Blob => isObjectOfType<Blob>('Blob')(value);
 
-is.nullOrUndefined = (value: unknown): value is null | undefined => is.null_(value) || is.undefined(value);
-is.object = (value: unknown): value is object => !is.null_(value) && (typeof value === 'object' || is.function_(value));
+is.nullOrUndefined = (value: unknown): value is null | undefined => is.null_(value) || is.undefined(value); // eslint-disable-line @typescript-eslint/ban-types
+
+is.object = (value: unknown): value is object => !is.null_(value) && (typeof value === 'object' || is.function_(value)); // eslint-disable-line @typescript-eslint/ban-types
+
 is.iterable = <T = unknown>(value: unknown): value is Iterable<T> => is.function_((value as Iterable<T>)?.[Symbol.iterator]);
 
 is.asyncIterable = <T = unknown>(value: unknown): value is AsyncIterable<T> => is.function_((value as AsyncIterable<T>)?.[Symbol.asyncIterator]);
@@ -195,11 +201,11 @@ is.asyncGenerator = (value: unknown): value is AsyncGenerator => is.asyncIterabl
 is.nativePromise = <T = unknown>(value: unknown): value is Promise<T> =>
 	isObjectOfType<Promise<T>>('Promise')(value);
 
-const hasPromiseAPI = <T = unknown>(value: unknown): value is Promise<T> =>
-	is.function_((value as Promise<T>)?.then) &&
-	is.function_((value as Promise<T>)?.catch);
+const hasPromiseApi = <T = unknown>(value: unknown): value is Promise<T> =>
+	is.function_((value as Promise<T>)?.then)
+		&& is.function_((value as Promise<T>)?.catch);
 
-is.promise = <T = unknown>(value: unknown): value is Promise<T> => is.nativePromise(value) || hasPromiseAPI(value);
+is.promise = <T = unknown>(value: unknown): value is Promise<T> => is.nativePromise(value) || hasPromiseApi(value);
 
 is.generatorFunction = isObjectOfType<GeneratorFunction>('GeneratorFunction');
 
@@ -211,12 +217,18 @@ is.asyncFunction = <T = unknown>(value: unknown): value is ((...args: any[]) =>
 is.boundFunction = (value: unknown): value is Function => is.function_(value) && !value.hasOwnProperty('prototype');
 
 is.regExp = isObjectOfType<RegExp>('RegExp');
+
 is.date = isObjectOfType<Date>('Date');
+
 is.error = isObjectOfType<Error>('Error');
+
 is.map = <Key = unknown, Value = unknown>(value: unknown): value is Map<Key, Value> => isObjectOfType<Map<Key, Value>>('Map')(value);
+
 is.set = <T = unknown>(value: unknown): value is Set<T> => isObjectOfType<Set<T>>('Set')(value);
-is.weakMap = <Key extends object = object, Value = unknown>(value: unknown): value is WeakMap<Key, Value> => isObjectOfType<WeakMap<Key, Value>>('WeakMap')(value);
-is.weakSet = (value: unknown): value is WeakSet<object> => isObjectOfType<WeakSet<object>>('WeakSet')(value);
+
+is.weakMap = <Key extends object = object, Value = unknown>(value: unknown): value is WeakMap<Key, Value> => isObjectOfType<WeakMap<Key, Value>>('WeakMap')(value); // eslint-disable-line @typescript-eslint/ban-types
+
+is.weakSet = (value: unknown): value is WeakSet<object> => isObjectOfType<WeakSet<object>>('WeakSet')(value); // eslint-disable-line @typescript-eslint/ban-types
 
 is.int8Array = isObjectOfType<Int8Array>('Int8Array');
 is.uint8Array = isObjectOfType<Uint8Array>('Uint8Array');
@@ -231,11 +243,15 @@ is.bigInt64Array = isObjectOfType<BigInt64Array>('BigInt64Array');
 is.bigUint64Array = isObjectOfType<BigUint64Array>('BigUint64Array');
 
 is.arrayBuffer = isObjectOfType<ArrayBuffer>('ArrayBuffer');
+
 is.sharedArrayBuffer = isObjectOfType<SharedArrayBuffer>('SharedArrayBuffer');
+
 is.dataView = isObjectOfType<DataView>('DataView');
+
 is.enumCase = <T = unknown>(value: unknown, targetEnum: T) => Object.values(targetEnum).includes(value as string);
 
 is.directInstanceOf = <T>(instance: unknown, class_: Class<T>): instance is T => Object.getPrototypeOf(instance) === class_.prototype;
+
 is.urlInstance = (value: unknown): value is URL => isObjectOfType<URL>('URL')(value);
 
 is.urlString = (value: unknown): value is string => {
@@ -252,7 +268,8 @@ is.urlString = (value: unknown): value is string => {
 };
 
 // Example: `is.truthy = (value: unknown): value is (not false | not 0 | not '' | not undefined | not null) => Boolean(value);`
-is.truthy = <T>(value: T | Falsy): value is T => Boolean(value);
+is.truthy = <T>(value: T | Falsy): value is T => Boolean(value); // eslint-disable-line unicorn/prefer-native-coercion-functions
+
 // Example: `is.falsy = (value: unknown): value is (not true | 0 | '' | undefined | null) => Boolean(value);`
 is.falsy = <T>(value: T | Falsy): value is Falsy => !value;
 
@@ -261,6 +278,7 @@ is.nan = (value: unknown) => Number.isNaN(value as number);
 is.primitive = (value: unknown): value is Primitive => is.null_(value) || isPrimitiveTypeName(typeof value);
 
 is.integer = (value: unknown): value is number => Number.isInteger(value as number);
+
 is.safeInteger = (value: unknown): value is number => Number.isSafeInteger(value as number);
 
 is.plainObject = <Value = unknown>(value: unknown): value is Record<PropertyKey, Value> => {
@@ -269,6 +287,7 @@ is.plainObject = <Value = unknown>(value: unknown): value is Record<PropertyKey,
 		return false;
 	}
 
+	// eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
 	const prototype = Object.getPrototypeOf(value);
 
 	return prototype === null || prototype === Object.getPrototypeOf({});
@@ -296,33 +315,35 @@ is.inRange = (value: number, range: number | number[]): value is number => {
 	throw new TypeError(`Invalid range: ${JSON.stringify(range)}`);
 };
 
+// eslint-disable-next-line @typescript-eslint/naming-convention
 const NODE_TYPE_ELEMENT = 1;
+
+// eslint-disable-next-line @typescript-eslint/naming-convention
 const DOM_PROPERTIES_TO_CHECK: Array<(keyof HTMLElement)> = [
 	'innerHTML',
 	'ownerDocument',
 	'style',
 	'attributes',
-	'nodeValue'
+	'nodeValue',
 ];
 
-is.domElement = (value: unknown): value is HTMLElement => {
-	return is.object(value) &&
-	(value as HTMLElement).nodeType === NODE_TYPE_ELEMENT &&
-	is.string((value as HTMLElement).nodeName) &&
-	!is.plainObject(value) &&
-	DOM_PROPERTIES_TO_CHECK.every(property => property in value);
-};
+is.domElement = (value: unknown): value is HTMLElement => is.object(value)
+	&& (value as HTMLElement).nodeType === NODE_TYPE_ELEMENT
+	&& is.string((value as HTMLElement).nodeName)
+	&& !is.plainObject(value)
+	&& DOM_PROPERTIES_TO_CHECK.every(property => property in value);
 
 is.observable = (value: unknown): value is ObservableLike => {
 	if (!value) {
 		return false;
 	}
 
-	// eslint-disable-next-line no-use-extend-native/no-use-extend-native
+	// eslint-disable-next-line no-use-extend-native/no-use-extend-native, @typescript-eslint/no-unsafe-call
 	if (value === (value as any)[Symbol.observable]?.()) {
 		return true;
 	}
 
+	// eslint-disable-next-line @typescript-eslint/no-unsafe-call
 	if (value === (value as any)['@@observable']?.()) {
 		return true;
 	}
@@ -336,13 +357,14 @@ export interface NodeStream extends NodeJS.EventEmitter {
 
 is.nodeStream = (value: unknown): value is NodeStream => is.object(value) && is.function_((value as NodeStream).pipe) && !is.observable(value);
 
-is.infinite = (value: unknown): value is number => value === Infinity || value === -Infinity;
+is.infinite = (value: unknown): value is number => value === Number.POSITIVE_INFINITY || value === Number.NEGATIVE_INFINITY;
 
 const isAbsoluteMod2 = (remainder: number) => (value: number): value is number => is.integer(value) && Math.abs(value % 2) === remainder;
 is.evenInteger = isAbsoluteMod2(0);
 is.oddInteger = isAbsoluteMod2(1);
 
 is.emptyArray = (value: unknown): value is never[] => is.array(value) && value.length === 0;
+
 is.nonEmptyArray = (value: unknown): value is unknown[] => is.array(value) && value.length > 0;
 
 is.emptyString = (value: unknown): value is '' => is.string(value) && value.length === 0;
@@ -356,20 +378,27 @@ is.nonEmptyString = (value: unknown): value is string => is.string(value) && val
 // TODO: Use `not ''` when the `not` operator is available.
 is.nonEmptyStringAndNotWhitespace = (value: unknown): value is string => is.string(value) && !is.emptyStringOrWhitespace(value);
 
+// eslint-disable-next-line unicorn/no-array-callback-reference
 is.emptyObject = <Key extends keyof any = string>(value: unknown): value is Record<Key, never> => is.object(value) && !is.map(value) && !is.set(value) && Object.keys(value).length === 0;
 
 // TODO: Use `not` operator here to remove `Map` and `Set` from type guard:
 // - https://github.com/Microsoft/TypeScript/pull/29317
+// eslint-disable-next-line unicorn/no-array-callback-reference
 is.nonEmptyObject = <Key extends keyof any = string, Value = unknown>(value: unknown): value is Record<Key, Value> => is.object(value) && !is.map(value) && !is.set(value) && Object.keys(value).length > 0;
 
 is.emptySet = (value: unknown): value is Set<never> => is.set(value) && value.size === 0;
+
 is.nonEmptySet = <T = unknown>(value: unknown): value is Set<T> => is.set(value) && value.size > 0;
 
+// eslint-disable-next-line unicorn/no-array-callback-reference
 is.emptyMap = (value: unknown): value is Map<never, never> => is.map(value) && value.size === 0;
+
+// eslint-disable-next-line unicorn/no-array-callback-reference
 is.nonEmptyMap = <Key = unknown, Value = unknown>(value: unknown): value is Map<Key, Value> => is.map(value) && value.size > 0;
 
 // `PropertyKey` is any value that can be used as an object key (string, number, or symbol)
 is.propertyKey = (value: unknown): value is PropertyKey => is.any([is.string, is.number, is.symbol], value);
+
 is.formData = (value: unknown): value is FormData => isObjectOfType<FormData>('FormData')(value);
 
 is.urlSearchParams = (value: unknown): value is URLSearchParams => isObjectOfType<URLSearchParams>('URLSearchParams')(value);
@@ -393,7 +422,7 @@ const predicateOnArray = (method: ArrayMethod, predicate: Predicate, values: unk
 is.any = (predicate: Predicate | Predicate[], ...values: unknown[]): boolean => {
 	const predicates = is.array(predicate) ? predicate : [predicate];
 	return predicates.some(singlePredicate =>
-		predicateOnArray(Array.prototype.some, singlePredicate, values)
+		predicateOnArray(Array.prototype.some, singlePredicate, values),
 	);
 };
 
@@ -402,13 +431,13 @@ is.all = (predicate: Predicate, ...values: unknown[]): boolean => predicateOnArr
 const assertType = (condition: boolean, description: string, value: unknown, options: {multipleValues?: boolean} = {}): asserts condition => {
 	if (!condition) {
 		const {multipleValues} = options;
-		const valuesMessage = multipleValues ?
-			`received values of types ${[
+		const valuesMessage = multipleValues
+			? `received values of types ${[
 				...new Set(
-					(value as any[]).map(singleValue => `\`${is(singleValue)}\``)
-				)
-			].join(', ')}` :
-			`received value of type \`${is(value)}\``;
+					(value as any[]).map(singleValue => `\`${is(singleValue)}\``),
+				),
+			].join(', ')}`
+			: `received value of type \`${is(value)}\``;
 
 		throw new TypeError(`Expected value which is \`${description}\`, ${valuesMessage}.`);
 	}
@@ -427,7 +456,7 @@ export const enum AssertionTypeDescription {
 	nan = 'NaN',
 	primitive = 'primitive',
 	integer = 'integer',
-	safeInteger = 'integer',
+	safeInteger = 'integer', // eslint-disable-line @typescript-eslint/no-duplicate-enum-values
 	plainObject = 'plain object',
 	arrayLike = 'array-like',
 	typedArray = 'TypedArray',
@@ -466,7 +495,7 @@ interface Assert {
 	bigint: (value: unknown) => asserts value is bigint;
 	// eslint-disable-next-line @typescript-eslint/ban-types
 	function_: (value: unknown) => asserts value is Function;
-	null_: (value: unknown) => asserts value is null;
+	null_: (value: unknown) => asserts value is null; // eslint-disable-line @typescript-eslint/ban-types
 	class_: (value: unknown) => asserts value is Class;
 	boolean: (value: unknown) => asserts value is boolean;
 	symbol: (value: unknown) => asserts value is symbol;
@@ -474,7 +503,7 @@ interface Assert {
 	array: <T = unknown>(value: unknown, assertion?: (element: unknown) => asserts element is T) => asserts value is T[];
 	buffer: (value: unknown) => asserts value is Buffer;
 	blob: (value: unknown) => asserts value is Blob;
-	nullOrUndefined: (value: unknown) => asserts value is null | undefined;
+	nullOrUndefined: (value: unknown) => asserts value is null | undefined; // eslint-disable-line @typescript-eslint/ban-types
 	object: <Key extends keyof any = string, Value = unknown>(value: unknown) => asserts value is Record<Key, Value>;
 	iterable: <T = unknown>(value: unknown) => asserts value is Iterable<T>;
 	asyncIterable: <T = unknown>(value: unknown) => asserts value is AsyncIterable<T>;
@@ -493,8 +522,8 @@ interface Assert {
 	error: (value: unknown) => asserts value is Error;
 	map: <Key = unknown, Value = unknown>(value: unknown) => asserts value is Map<Key, Value>;
 	set: <T = unknown>(value: unknown) => asserts value is Set<T>;
-	weakMap: <Key extends object = object, Value = unknown>(value: unknown) => asserts value is WeakMap<Key, Value>;
-	weakSet: <T extends object = object>(value: unknown) => asserts value is WeakSet<T>;
+	weakMap: <Key extends object = object, Value = unknown>(value: unknown) => asserts value is WeakMap<Key, Value>; // eslint-disable-line @typescript-eslint/ban-types
+	weakSet: <T extends object = object>(value: unknown) => asserts value is WeakSet<T>; // eslint-disable-line @typescript-eslint/ban-types
 	int8Array: (value: unknown) => asserts value is Int8Array;
 	uint8Array: (value: unknown) => asserts value is Uint8Array;
 	uint8ClampedArray: (value: unknown) => asserts value is Uint8ClampedArray;
@@ -554,6 +583,7 @@ interface Assert {
 	all: (predicate: Predicate, ...values: unknown[]) => void | never;
 }
 
+/* eslint-disable @typescript-eslint/no-confusing-void-expression */
 export const assert: Assert = {
 	// Unknowns.
 	undefined: (value: unknown): asserts value is undefined => assertType(is.undefined(value), 'undefined', value),
@@ -562,23 +592,24 @@ export const assert: Assert = {
 	bigint: (value: unknown): asserts value is bigint => assertType(is.bigint(value), 'bigint', value),
 	// eslint-disable-next-line @typescript-eslint/ban-types
 	function_: (value: unknown): asserts value is Function => assertType(is.function_(value), 'Function', value),
-	null_: (value: unknown): asserts value is null => assertType(is.null_(value), 'null', value),
+	null_: (value: unknown): asserts value is null => assertType(is.null_(value), 'null', value), // eslint-disable-line @typescript-eslint/ban-types
 	class_: (value: unknown): asserts value is Class => assertType(is.class_(value), AssertionTypeDescription.class_, value),
 	boolean: (value: unknown): asserts value is boolean => assertType(is.boolean(value), 'boolean', value),
 	symbol: (value: unknown): asserts value is symbol => assertType(is.symbol(value), 'symbol', value),
 	numericString: (value: unknown): asserts value is string => assertType(is.numericString(value), AssertionTypeDescription.numericString, value),
-	array: <T = unknown>(value: unknown, assertion?: (element: unknown) => asserts element is T): asserts value is T[] => {
+	array: <T = unknown>(value: unknown, assertion?: (element: unknown) => asserts element is T): asserts value is T[] => { // eslint-disable-line object-shorthand
 		const assert: (condition: boolean, description: string, value: unknown) => asserts condition = assertType;
 		assert(is.array(value), 'Array', value);
 
 		if (assertion) {
+			// eslint-disable-next-line unicorn/no-array-for-each, unicorn/no-array-callback-reference
 			value.forEach(assertion);
 		}
 	},
 	buffer: (value: unknown): asserts value is Buffer => assertType(is.buffer(value), 'Buffer', value),
 	blob: (value: unknown): asserts value is Blob => assertType(is.blob(value), 'Blob', value),
-	nullOrUndefined: (value: unknown): asserts value is null | undefined => assertType(is.nullOrUndefined(value), AssertionTypeDescription.nullOrUndefined, value),
-	object: (value: unknown): asserts value is object => assertType(is.object(value), 'Object', value),
+	nullOrUndefined: (value: unknown): asserts value is null | undefined => assertType(is.nullOrUndefined(value), AssertionTypeDescription.nullOrUndefined, value), // eslint-disable-line @typescript-eslint/ban-types
+	object: (value: unknown): asserts value is object => assertType(is.object(value), 'Object', value), // eslint-disable-line @typescript-eslint/ban-types
 	iterable: <T = unknown>(value: unknown): asserts value is Iterable<T> => assertType(is.iterable(value), AssertionTypeDescription.iterable, value),
 	asyncIterable: <T = unknown>(value: unknown): asserts value is AsyncIterable<T> => assertType(is.asyncIterable(value), AssertionTypeDescription.asyncIterable, value),
 	generator: (value: unknown): asserts value is Generator => assertType(is.generator(value), 'Generator', value),
@@ -594,10 +625,10 @@ export const assert: Assert = {
 	regExp: (value: unknown): asserts value is RegExp => assertType(is.regExp(value), 'RegExp', value),
 	date: (value: unknown): asserts value is Date => assertType(is.date(value), 'Date', value),
 	error: (value: unknown): asserts value is Error => assertType(is.error(value), 'Error', value),
-	map: <Key = unknown, Value = unknown>(value: unknown): asserts value is Map<Key, Value> => assertType(is.map(value), 'Map', value),
+	map: <Key = unknown, Value = unknown>(value: unknown): asserts value is Map<Key, Value> => assertType(is.map(value), 'Map', value), // eslint-disable-line unicorn/no-array-callback-reference
 	set: <T = unknown>(value: unknown): asserts value is Set<T> => assertType(is.set(value), 'Set', value),
-	weakMap: <Key extends object = object, Value = unknown>(value: unknown): asserts value is WeakMap<Key, Value> => assertType(is.weakMap(value), 'WeakMap', value),
-	weakSet: <T extends object = object>(value: unknown): asserts value is WeakSet<T> => assertType(is.weakSet(value), 'WeakSet', value),
+	weakMap: <Key extends object = object, Value = unknown>(value: unknown): asserts value is WeakMap<Key, Value> => assertType(is.weakMap(value), 'WeakMap', value), // eslint-disable-line @typescript-eslint/ban-types
+	weakSet: <T extends object = object>(value: unknown): asserts value is WeakSet<T> => assertType(is.weakSet(value), 'WeakSet', value), // eslint-disable-line @typescript-eslint/ban-types
 	int8Array: (value: unknown): asserts value is Int8Array => assertType(is.int8Array(value), 'Int8Array', value),
 	uint8Array: (value: unknown): asserts value is Uint8Array => assertType(is.uint8Array(value), 'Uint8Array', value),
 	uint8ClampedArray: (value: unknown): asserts value is Uint8ClampedArray => assertType(is.uint8ClampedArray(value), 'Uint8ClampedArray', value),
@@ -653,42 +684,36 @@ export const assert: Assert = {
 	inRange: (value: number, range: number | number[]): asserts value is number => assertType(is.inRange(value, range), AssertionTypeDescription.inRange, value),
 
 	// Variadic functions.
-	any: (predicate: Predicate | Predicate[], ...values: unknown[]): void | never => {
-		return assertType(is.any(predicate, ...values), AssertionTypeDescription.any, values, {multipleValues: true});
-	},
-	all: (predicate: Predicate, ...values: unknown[]): void | never => assertType(is.all(predicate, ...values), AssertionTypeDescription.all, values, {multipleValues: true})
+	any: (predicate: Predicate | Predicate[], ...values: unknown[]): void | never => assertType(is.any(predicate, ...values), AssertionTypeDescription.any, values, {multipleValues: true}),
+	all: (predicate: Predicate, ...values: unknown[]): void | never => assertType(is.all(predicate, ...values), AssertionTypeDescription.all, values, {multipleValues: true}),
 };
+/* eslint-enable @typescript-eslint/no-confusing-void-expression */
 
 // Some few keywords are reserved, but we'll populate them for Node.js users
 // See https://github.com/Microsoft/TypeScript/issues/2536
 Object.defineProperties(is, {
 	class: {
-		value: is.class_
+		value: is.class_,
 	},
 	function: {
-		value: is.function_
+		value: is.function_,
 	},
 	null: {
-		value: is.null_
-	}
+		value: is.null_,
+	},
 });
 Object.defineProperties(assert, {
 	class: {
-		value: assert.class_
+		value: assert.class_,
 	},
 	function: {
-		value: assert.function_
+		value: assert.function_,
 	},
 	null: {
-		value: assert.null_
-	}
+		value: assert.null_,
+	},
 });
 
 export default is;
 
-export {Class, TypedArray, ObservableLike, Primitive} from './types';
-
-// For CommonJS default export support
-module.exports = is;
-module.exports.default = is;
-module.exports.assert = assert;
+export type {Class, TypedArray, ObservableLike, Primitive} from './types.js';

source/types.ts

@@ -4,7 +4,7 @@
 Matches any [primitive value](https://developer.mozilla.org/en-US/docs/Glossary/Primitive).
 */
 export type Primitive =
-	| null
+	| null // eslint-disable-line @typescript-eslint/ban-types
 	| undefined
 	| string
 	| number
@@ -12,7 +12,6 @@ export type Primitive =
 	| symbol
 	| bigint;
 
-// TODO: Remove the `= unknown` sometime  in the future when most users are on TS 3.5 as it's now the default
 /**
 Matches a [`class` constructor](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes).
 */
@@ -48,4 +47,5 @@ export interface ObservableLike {
 	[Symbol.observable](): ObservableLike;
 }
 
+// eslint-disable-next-line @typescript-eslint/ban-types
 export type Falsy = false | 0 | 0n | '' | null | undefined;

tsconfig.json

@@ -1,14 +1,14 @@
 {
 	"extends": "@sindresorhus/tsconfig",
 	"compilerOptions": {
-		"outDir": "dist",
-		"target": "es2018",
-		"lib": [
-			"es2018",
-			"dom"
-		]
+		"outDir": "dist"
 	},
 	"include": [
 		"source"
-	]
+	],
+	"ts-node": {
+		"transpileOnly": true,
+		"files": true,
+		"experimentalResolver": true
+	}
 }

tsconfig.xo.json

@@ -1,6 +0,0 @@
-{
-	"extends": "./tsconfig.json",
-	"include": [
-		"test"
-	]
-}