/** * The `util` module supports the needs of Node.js internal APIs. Many of the * utilities are useful for application and module developers as well. To access * it: * * ```js * const util = require('util'); * ``` * @see [source](https://github.com/nodejs/node/blob/v18.0.0/lib/util.js) */ declare module 'util' { import * as types from 'node:util/types'; export interface InspectOptions { /** * If set to `true`, getters are going to be * inspected as well. If set to `'get'` only getters without setter are going * to be inspected. If set to `'set'` only getters having a corresponding * setter are going to be inspected. This might cause side effects depending on * the getter function. * @default `false` */ getters?: 'get' | 'set' | boolean | undefined; showHidden?: boolean | undefined; /** * @default 2 */ depth?: number | null | undefined; colors?: boolean | undefined; customInspect?: boolean | undefined; showProxy?: boolean | undefined; maxArrayLength?: number | null | undefined; /** * Specifies the maximum number of characters to * include when formatting. Set to `null` or `Infinity` to show all elements. * Set to `0` or negative to show no characters. * @default 10000 */ maxStringLength?: number | null | undefined; breakLength?: number | undefined; /** * Setting this to `false` causes each object key * to be displayed on a new line. It will also add new lines to text that is * longer than `breakLength`. If set to a number, the most `n` inner elements * are united on a single line as long as all properties fit into * `breakLength`. Short array elements are also grouped together. Note that no * text will be reduced below 16 characters, no matter the `breakLength` size. * For more information, see the example below. * @default `true` */ compact?: boolean | number | undefined; sorted?: boolean | ((a: string, b: string) => number) | undefined; } export type Style = 'special' | 'number' | 'bigint' | 'boolean' | 'undefined' | 'null' | 'string' | 'symbol' | 'date' | 'regexp' | 'module'; export type CustomInspectFunction = (depth: number, options: InspectOptionsStylized) => string; export interface InspectOptionsStylized extends InspectOptions { stylize(text: string, styleType: Style): string; } /** * The `util.format()` method returns a formatted string using the first argument * as a `printf`\-like format string which can contain zero or more format * specifiers. Each specifier is replaced with the converted value from the * corresponding argument. Supported specifiers are: * * If a specifier does not have a corresponding argument, it is not replaced: * * ```js * util.format('%s:%s', 'foo'); * // Returns: 'foo:%s' * ``` * * Values that are not part of the format string are formatted using`util.inspect()` if their type is not `string`. * * If there are more arguments passed to the `util.format()` method than the * number of specifiers, the extra arguments are concatenated to the returned * string, separated by spaces: * * ```js * util.format('%s:%s', 'foo', 'bar', 'baz'); * // Returns: 'foo:bar baz' * ``` * * If the first argument does not contain a valid format specifier, `util.format()`returns a string that is the concatenation of all arguments separated by spaces: * * ```js * util.format(1, 2, 3); * // Returns: '1 2 3' * ``` * * If only one argument is passed to `util.format()`, it is returned as it is * without any formatting: * * ```js * util.format('%% %s'); * // Returns: '%% %s' * ``` * * `util.format()` is a synchronous method that is intended as a debugging tool. * Some input values can have a significant performance overhead that can block the * event loop. Use this function with care and never in a hot code path. * @since v0.5.3 * @param format A `printf`-like format string. */ export function format(format?: any, ...param: any[]): string; /** * This function is identical to {@link format}, except in that it takes * an `inspectOptions` argument which specifies options that are passed along to {@link inspect}. * * ```js * util.formatWithOptions({ colors: true }, 'See object %O', { foo: 42 }); * // Returns 'See object { foo: 42 }', where `42` is colored as a number * // when printed to a terminal. * ``` * @since v10.0.0 */ export function formatWithOptions(inspectOptions: InspectOptions, format?: any, ...param: any[]): string; /** * Returns the string name for a numeric error code that comes from a Node.js API. * The mapping between error codes and error names is platform-dependent. * See `Common System Errors` for the names of common errors. * * ```js * fs.access('file/that/does/not/exist', (err) => { * const name = util.getSystemErrorName(err.errno); * console.error(name); // ENOENT * }); * ``` * @since v9.7.0 */ export function getSystemErrorName(err: number): string; /** * Returns a Map of all system error codes available from the Node.js API. * The mapping between error codes and error names is platform-dependent. * See `Common System Errors` for the names of common errors. * * ```js * fs.access('file/that/does/not/exist', (err) => { * const errorMap = util.getSystemErrorMap(); * const name = errorMap.get(err.errno); * console.error(name); // ENOENT * }); * ``` * @since v16.0.0, v14.17.0 */ export function getSystemErrorMap(): Map; /** * The `util.log()` method prints the given `string` to `stdout` with an included * timestamp. * * ```js * const util = require('util'); * * util.log('Timestamped message.'); * ``` * @since v0.3.0 * @deprecated Since v6.0.0 - Use a third party module instead. */ export function log(string: string): void; /** * Returns the `string` after replacing any surrogate code points * (or equivalently, any unpaired surrogate code units) with the * Unicode "replacement character" U+FFFD. * @since v16.8.0, v14.18.0 */ export function toUSVString(string: string): string; /** * The `util.inspect()` method returns a string representation of `object` that is * intended for debugging. The output of `util.inspect` may change at any time * and should not be depended upon programmatically. Additional `options` may be * passed that alter the result.`util.inspect()` will use the constructor's name and/or `@@toStringTag` to make * an identifiable tag for an inspected value. * * ```js * class Foo { * get [Symbol.toStringTag]() { * return 'bar'; * } * } * * class Bar {} * * const baz = Object.create(null, { [Symbol.toStringTag]: { value: 'foo' } }); * * util.inspect(new Foo()); // 'Foo [bar] {}' * util.inspect(new Bar()); // 'Bar {}' * util.inspect(baz); // '[foo] {}' * ``` * * Circular references point to their anchor by using a reference index: * * ```js * const { inspect } = require('util'); * * const obj = {}; * obj.a = [obj]; * obj.b = {}; * obj.b.inner = obj.b; * obj.b.obj = obj; * * console.log(inspect(obj)); * // { * // a: [ [Circular *1] ], * // b: { inner: [Circular *2], obj: [Circular *1] } * // } * ``` * * The following example inspects all properties of the `util` object: * * ```js * const util = require('util'); * * console.log(util.inspect(util, { showHidden: true, depth: null })); * ``` * * The following example highlights the effect of the `compact` option: * * ```js * const util = require('util'); * * const o = { * a: [1, 2, [[ * 'Lorem ipsum dolor sit amet,\nconsectetur adipiscing elit, sed do ' + * 'eiusmod \ntempor incididunt ut labore et dolore magna aliqua.', * 'test', * 'foo']], 4], * b: new Map([['za', 1], ['zb', 'test']]) * }; * console.log(util.inspect(o, { compact: true, depth: 5, breakLength: 80 })); * * // { a: * // [ 1, * // 2, * // [ [ 'Lorem ipsum dolor sit amet,\nconsectetur [...]', // A long line * // 'test', * // 'foo' ] ], * // 4 ], * // b: Map(2) { 'za' => 1, 'zb' => 'test' } } * * // Setting `compact` to false or an integer creates more reader friendly output. * console.log(util.inspect(o, { compact: false, depth: 5, breakLength: 80 })); * * // { * // a: [ * // 1, * // 2, * // [ * // [ * // 'Lorem ipsum dolor sit amet,\n' + * // 'consectetur adipiscing elit, sed do eiusmod \n' + * // 'tempor incididunt ut labore et dolore magna aliqua.', * // 'test', * // 'foo' * // ] * // ], * // 4 * // ], * // b: Map(2) { * // 'za' => 1, * // 'zb' => 'test' * // } * // } * * // Setting `breakLength` to e.g. 150 will print the "Lorem ipsum" text in a * // single line. * ``` * * The `showHidden` option allows [`WeakMap`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap) and * [`WeakSet`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakSet) entries to be * inspected. If there are more entries than `maxArrayLength`, there is no * guarantee which entries are displayed. That means retrieving the same [`WeakSet`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakSet) entries twice may * result in different output. Furthermore, entries * with no remaining strong references may be garbage collected at any time. * * ```js * const { inspect } = require('util'); * * const obj = { a: 1 }; * const obj2 = { b: 2 }; * const weakSet = new WeakSet([obj, obj2]); * * console.log(inspect(weakSet, { showHidden: true })); * // WeakSet { { a: 1 }, { b: 2 } } * ``` * * The `sorted` option ensures that an object's property insertion order does not * impact the result of `util.inspect()`. * * ```js * const { inspect } = require('util'); * const assert = require('assert'); * * const o1 = { * b: [2, 3, 1], * a: '`a` comes before `b`', * c: new Set([2, 3, 1]) * }; * console.log(inspect(o1, { sorted: true })); * // { a: '`a` comes before `b`', b: [ 2, 3, 1 ], c: Set(3) { 1, 2, 3 } } * console.log(inspect(o1, { sorted: (a, b) => b.localeCompare(a) })); * // { c: Set(3) { 3, 2, 1 }, b: [ 2, 3, 1 ], a: '`a` comes before `b`' } * * const o2 = { * c: new Set([2, 1, 3]), * a: '`a` comes before `b`', * b: [2, 3, 1] * }; * assert.strict.equal( * inspect(o1, { sorted: true }), * inspect(o2, { sorted: true }) * ); * ``` * * The `numericSeparator` option adds an underscore every three digits to all * numbers. * * ```js * const { inspect } = require('util'); * * const thousand = 1_000; * const million = 1_000_000; * const bigNumber = 123_456_789n; * const bigDecimal = 1_234.123_45; * * console.log(thousand, million, bigNumber, bigDecimal); * // 1_000 1_000_000 123_456_789n 1_234.123_45 * ``` * * `util.inspect()` is a synchronous method intended for debugging. Its maximum * output length is approximately 128 MB. Inputs that result in longer output will * be truncated. * @since v0.3.0 * @param object Any JavaScript primitive or `Object`. * @return The representation of `object`. */ export function inspect(object: any, showHidden?: boolean, depth?: number | null, color?: boolean): string; export function inspect(object: any, options?: InspectOptions): string; export namespace inspect { let colors: NodeJS.Dict<[number, number]>; let styles: { [K in Style]: string; }; let defaultOptions: InspectOptions; /** * Allows changing inspect settings from the repl. */ let replDefaults: InspectOptions; /** * That can be used to declare custom inspect functions. */ const custom: unique symbol; } /** * Alias for [`Array.isArray()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/isArray). * * Returns `true` if the given `object` is an `Array`. Otherwise, returns `false`. * * ```js * const util = require('util'); * * util.isArray([]); * // Returns: true * util.isArray(new Array()); * // Returns: true * util.isArray({}); * // Returns: false * ``` * @since v0.6.0 * @deprecated Since v4.0.0 - Use `isArray` instead. */ export function isArray(object: unknown): object is unknown[]; /** * Returns `true` if the given `object` is a `RegExp`. Otherwise, returns `false`. * * ```js * const util = require('util'); * * util.isRegExp(/some regexp/); * // Returns: true * util.isRegExp(new RegExp('another regexp')); * // Returns: true * util.isRegExp({}); * // Returns: false * ``` * @since v0.6.0 * @deprecated Since v4.0.0 - Deprecated */ export function isRegExp(object: unknown): object is RegExp; /** * Returns `true` if the given `object` is a `Date`. Otherwise, returns `false`. * * ```js * const util = require('util'); * * util.isDate(new Date()); * // Returns: true * util.isDate(Date()); * // false (without 'new' returns a String) * util.isDate({}); * // Returns: false * ``` * @since v0.6.0 * @deprecated Since v4.0.0 - Use {@link types.isDate} instead. */ export function isDate(object: unknown): object is Date; /** * Returns `true` if the given `object` is an `Error`. Otherwise, returns`false`. * * ```js * const util = require('util'); * * util.isError(new Error()); * // Returns: true * util.isError(new TypeError()); * // Returns: true * util.isError({ name: 'Error', message: 'an error occurred' }); * // Returns: false * ``` * * This method relies on `Object.prototype.toString()` behavior. It is * possible to obtain an incorrect result when the `object` argument manipulates`@@toStringTag`. * * ```js * const util = require('util'); * const obj = { name: 'Error', message: 'an error occurred' }; * * util.isError(obj); * // Returns: false * obj[Symbol.toStringTag] = 'Error'; * util.isError(obj); * // Returns: true * ``` * @since v0.6.0 * @deprecated Since v4.0.0 - Use {@link types.isNativeError} instead. */ export function isError(object: unknown): object is Error; /** * Usage of `util.inherits()` is discouraged. Please use the ES6 `class` and`extends` keywords to get language level inheritance support. Also note * that the two styles are [semantically incompatible](https://github.com/nodejs/node/issues/4179). * * Inherit the prototype methods from one [constructor](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/constructor) into another. The * prototype of `constructor` will be set to a new object created from`superConstructor`. * * This mainly adds some input validation on top of`Object.setPrototypeOf(constructor.prototype, superConstructor.prototype)`. * As an additional convenience, `superConstructor` will be accessible * through the `constructor.super_` property. * * ```js * const util = require('util'); * const EventEmitter = require('events'); * * function MyStream() { * EventEmitter.call(this); * } * * util.inherits(MyStream, EventEmitter); * * MyStream.prototype.write = function(data) { * this.emit('data', data); * }; * * const stream = new MyStream(); * * console.log(stream instanceof EventEmitter); // true * console.log(MyStream.super_ === EventEmitter); // true * * stream.on('data', (data) => { * console.log(`Received data: "${data}"`); * }); * stream.write('It works!'); // Received data: "It works!" * ``` * * ES6 example using `class` and `extends`: * * ```js * const EventEmitter = require('events'); * * class MyStream extends EventEmitter { * write(data) { * this.emit('data', data); * } * } * * const stream = new MyStream(); * * stream.on('data', (data) => { * console.log(`Received data: "${data}"`); * }); * stream.write('With ES6'); * ``` * @since v0.3.0 * @deprecated Legacy: Use ES2015 class syntax and `extends` keyword instead. */ export function inherits(constructor: unknown, superConstructor: unknown): void; export type DebugLoggerFunction = (msg: string, ...param: unknown[]) => void; export interface DebugLogger extends DebugLoggerFunction { enabled: boolean; } /** * The `util.debuglog()` method is used to create a function that conditionally * writes debug messages to `stderr` based on the existence of the `NODE_DEBUG`environment variable. If the `section` name appears within the value of that * environment variable, then the returned function operates similar to `console.error()`. If not, then the returned function is a no-op. * * ```js * const util = require('util'); * const debuglog = util.debuglog('foo'); * * debuglog('hello from foo [%d]', 123); * ``` * * If this program is run with `NODE_DEBUG=foo` in the environment, then * it will output something like: * * ```console * FOO 3245: hello from foo [123] * ``` * * where `3245` is the process id. If it is not run with that * environment variable set, then it will not print anything. * * The `section` supports wildcard also: * * ```js * const util = require('util'); * const debuglog = util.debuglog('foo-bar'); * * debuglog('hi there, it\'s foo-bar [%d]', 2333); * ``` * * if it is run with `NODE_DEBUG=foo*` in the environment, then it will output * something like: * * ```console * FOO-BAR 3257: hi there, it's foo-bar [2333] * ``` * * Multiple comma-separated `section` names may be specified in the `NODE_DEBUG`environment variable: `NODE_DEBUG=fs,net,tls`. * * The optional `callback` argument can be used to replace the logging function * with a different function that doesn't have any initialization or * unnecessary wrapping. * * ```js * const util = require('util'); * let debuglog = util.debuglog('internals', (debug) => { * // Replace with a logging function that optimizes out * // testing if the section is enabled * debuglog = debug; * }); * ``` * @since v0.11.3 * @param section A string identifying the portion of the application for which the `debuglog` function is being created. * @param callback A callback invoked the first time the logging function is called with a function argument that is a more optimized logging function. * @return The logging function */ export function debuglog(section: string, callback?: (fn: DebugLoggerFunction) => void): DebugLogger; export const debug: typeof debuglog; /** * Returns `true` if the given `object` is a `Boolean`. Otherwise, returns `false`. * * ```js * const util = require('util'); * * util.isBoolean(1); * // Returns: false * util.isBoolean(0); * // Returns: false * util.isBoolean(false); * // Returns: true * ``` * @since v0.11.5 * @deprecated Since v4.0.0 - Use `typeof value === 'boolean'` instead. */ export function isBoolean(object: unknown): object is boolean; /** * Returns `true` if the given `object` is a `Buffer`. Otherwise, returns `false`. * * ```js * const util = require('util'); * * util.isBuffer({ length: 0 }); * // Returns: false * util.isBuffer([]); * // Returns: false * util.isBuffer(Buffer.from('hello world')); * // Returns: true * ``` * @since v0.11.5 * @deprecated Since v4.0.0 - Use `isBuffer` instead. */ export function isBuffer(object: unknown): object is Buffer; /** * Returns `true` if the given `object` is a `Function`. Otherwise, returns`false`. * * ```js * const util = require('util'); * * function Foo() {} * const Bar = () => {}; * * util.isFunction({}); * // Returns: false * util.isFunction(Foo); * // Returns: true * util.isFunction(Bar); * // Returns: true * ``` * @since v0.11.5 * @deprecated Since v4.0.0 - Use `typeof value === 'function'` instead. */ export function isFunction(object: unknown): boolean; /** * Returns `true` if the given `object` is strictly `null`. Otherwise, returns`false`. * * ```js * const util = require('util'); * * util.isNull(0); * // Returns: false * util.isNull(undefined); * // Returns: false * util.isNull(null); * // Returns: true * ``` * @since v0.11.5 * @deprecated Since v4.0.0 - Use `value === null` instead. */ export function isNull(object: unknown): object is null; /** * Returns `true` if the given `object` is `null` or `undefined`. Otherwise, * returns `false`. * * ```js * const util = require('util'); * * util.isNullOrUndefined(0); * // Returns: false * util.isNullOrUndefined(undefined); * // Returns: true * util.isNullOrUndefined(null); * // Returns: true * ``` * @since v0.11.5 * @deprecated Since v4.0.0 - Use `value === undefined || value === null` instead. */ export function isNullOrUndefined(object: unknown): object is null | undefined; /** * Returns `true` if the given `object` is a `Number`. Otherwise, returns `false`. * * ```js * const util = require('util'); * * util.isNumber(false); * // Returns: false * util.isNumber(Infinity); * // Returns: true * util.isNumber(0); * // Returns: true * util.isNumber(NaN); * // Returns: true * ``` * @since v0.11.5 * @deprecated Since v4.0.0 - Use `typeof value === 'number'` instead. */ export function isNumber(object: unknown): object is number; /** * Returns `true` if the given `object` is strictly an `Object`**and** not a`Function` (even though functions are objects in JavaScript). * Otherwise, returns `false`. * * ```js * const util = require('util'); * * util.isObject(5); * // Returns: false * util.isObject(null); * // Returns: false * util.isObject({}); * // Returns: true * util.isObject(() => {}); * // Returns: false * ``` * @since v0.11.5 * @deprecated Since v4.0.0 - Deprecated: Use `value !== null && typeof value === 'object'` instead. */ export function isObject(object: unknown): boolean; /** * Returns `true` if the given `object` is a primitive type. Otherwise, returns`false`. * * ```js * const util = require('util'); * * util.isPrimitive(5); * // Returns: true * util.isPrimitive('foo'); * // Returns: true * util.isPrimitive(false); * // Returns: true * util.isPrimitive(null); * // Returns: true * util.isPrimitive(undefined); * // Returns: true * util.isPrimitive({}); * // Returns: false * util.isPrimitive(() => {}); * // Returns: false * util.isPrimitive(/^$/); * // Returns: false * util.isPrimitive(new Date()); * // Returns: false * ``` * @since v0.11.5 * @deprecated Since v4.0.0 - Use `(typeof value !== 'object' && typeof value !== 'function') || value === null` instead. */ export function isPrimitive(object: unknown): boolean; /** * Returns `true` if the given `object` is a `string`. Otherwise, returns `false`. * * ```js * const util = require('util'); * * util.isString(''); * // Returns: true * util.isString('foo'); * // Returns: true * util.isString(String('foo')); * // Returns: true * util.isString(5); * // Returns: false * ``` * @since v0.11.5 * @deprecated Since v4.0.0 - Use `typeof value === 'string'` instead. */ export function isString(object: unknown): object is string; /** * Returns `true` if the given `object` is a `Symbol`. Otherwise, returns `false`. * * ```js * const util = require('util'); * * util.isSymbol(5); * // Returns: false * util.isSymbol('foo'); * // Returns: false * util.isSymbol(Symbol('foo')); * // Returns: true * ``` * @since v0.11.5 * @deprecated Since v4.0.0 - Use `typeof value === 'symbol'` instead. */ export function isSymbol(object: unknown): object is symbol; /** * Returns `true` if the given `object` is `undefined`. Otherwise, returns `false`. * * ```js * const util = require('util'); * * const foo = undefined; * util.isUndefined(5); * // Returns: false * util.isUndefined(foo); * // Returns: true * util.isUndefined(null); * // Returns: false * ``` * @since v0.11.5 * @deprecated Since v4.0.0 - Use `value === undefined` instead. */ export function isUndefined(object: unknown): object is undefined; /** * The `util.deprecate()` method wraps `fn` (which may be a function or class) in * such a way that it is marked as deprecated. * * ```js * const util = require('util'); * * exports.obsoleteFunction = util.deprecate(() => { * // Do something here. * }, 'obsoleteFunction() is deprecated. Use newShinyFunction() instead.'); * ``` * * When called, `util.deprecate()` will return a function that will emit a`DeprecationWarning` using the `'warning'` event. The warning will * be emitted and printed to `stderr` the first time the returned function is * called. After the warning is emitted, the wrapped function is called without * emitting a warning. * * If the same optional `code` is supplied in multiple calls to `util.deprecate()`, * the warning will be emitted only once for that `code`. * * ```js * const util = require('util'); * * const fn1 = util.deprecate(someFunction, someMessage, 'DEP0001'); * const fn2 = util.deprecate(someOtherFunction, someOtherMessage, 'DEP0001'); * fn1(); // Emits a deprecation warning with code DEP0001 * fn2(); // Does not emit a deprecation warning because it has the same code * ``` * * If either the `--no-deprecation` or `--no-warnings` command-line flags are * used, or if the `process.noDeprecation` property is set to `true`_prior_ to * the first deprecation warning, the `util.deprecate()` method does nothing. * * If the `--trace-deprecation` or `--trace-warnings` command-line flags are set, * or the `process.traceDeprecation` property is set to `true`, a warning and a * stack trace are printed to `stderr` the first time the deprecated function is * called. * * If the `--throw-deprecation` command-line flag is set, or the`process.throwDeprecation` property is set to `true`, then an exception will be * thrown when the deprecated function is called. * * The `--throw-deprecation` command-line flag and `process.throwDeprecation`property take precedence over `--trace-deprecation` and`process.traceDeprecation`. * @since v0.8.0 * @param fn The function that is being deprecated. * @param msg A warning message to display when the deprecated function is invoked. * @param code A deprecation code. See the `list of deprecated APIs` for a list of codes. * @return The deprecated function wrapped to emit a warning. */ export function deprecate(fn: T, msg: string, code?: string): T; /** * Returns `true` if there is deep strict equality between `val1` and `val2`. * Otherwise, returns `false`. * * See `assert.deepStrictEqual()` for more information about deep strict * equality. * @since v9.0.0 */ export function isDeepStrictEqual(val1: unknown, val2: unknown): boolean; /** * Returns `str` with any ANSI escape codes removed. * * ```js * console.log(util.stripVTControlCharacters('\u001B[4mvalue\u001B[0m')); * // Prints "value" * ``` * @since v16.11.0 */ export function stripVTControlCharacters(str: string): string; /** * Takes an `async` function (or a function that returns a `Promise`) and returns a * function following the error-first callback style, i.e. taking * an `(err, value) => ...` callback as the last argument. In the callback, the * first argument will be the rejection reason (or `null` if the `Promise`resolved), and the second argument will be the resolved value. * * ```js * const util = require('util'); * * async function fn() { * return 'hello world'; * } * const callbackFunction = util.callbackify(fn); * * callbackFunction((err, ret) => { * if (err) throw err; * console.log(ret); * }); * ``` * * Will print: * * ```text * hello world * ``` * * The callback is executed asynchronously, and will have a limited stack trace. * If the callback throws, the process will emit an `'uncaughtException'` event, and if not handled will exit. * * Since `null` has a special meaning as the first argument to a callback, if a * wrapped function rejects a `Promise` with a falsy value as a reason, the value * is wrapped in an `Error` with the original value stored in a field named`reason`. * * ```js * function fn() { * return Promise.reject(null); * } * const callbackFunction = util.callbackify(fn); * * callbackFunction((err, ret) => { * // When the Promise was rejected with `null` it is wrapped with an Error and * // the original value is stored in `reason`. * err && Object.hasOwn(err, 'reason') && err.reason === null; // true * }); * ``` * @since v8.2.0 * @param original An `async` function * @return a callback style function */ export function callbackify(fn: () => Promise): (callback: (err: NodeJS.ErrnoException) => void) => void; export function callbackify(fn: () => Promise): (callback: (err: NodeJS.ErrnoException, result: TResult) => void) => void; export function callbackify(fn: (arg1: T1) => Promise): (arg1: T1, callback: (err: NodeJS.ErrnoException) => void) => void; export function callbackify(fn: (arg1: T1) => Promise): (arg1: T1, callback: (err: NodeJS.ErrnoException, result: TResult) => void) => void; export function callbackify(fn: (arg1: T1, arg2: T2) => Promise): (arg1: T1, arg2: T2, callback: (err: NodeJS.ErrnoException) => void) => void; export function callbackify(fn: (arg1: T1, arg2: T2) => Promise): (arg1: T1, arg2: T2, callback: (err: NodeJS.ErrnoException | null, result: TResult) => void) => void; export function callbackify(fn: (arg1: T1, arg2: T2, arg3: T3) => Promise): (arg1: T1, arg2: T2, arg3: T3, callback: (err: NodeJS.ErrnoException) => void) => void; export function callbackify( fn: (arg1: T1, arg2: T2, arg3: T3) => Promise ): (arg1: T1, arg2: T2, arg3: T3, callback: (err: NodeJS.ErrnoException | null, result: TResult) => void) => void; export function callbackify( fn: (arg1: T1, arg2: T2, arg3: T3, arg4: T4) => Promise ): (arg1: T1, arg2: T2, arg3: T3, arg4: T4, callback: (err: NodeJS.ErrnoException) => void) => void; export function callbackify( fn: (arg1: T1, arg2: T2, arg3: T3, arg4: T4) => Promise ): (arg1: T1, arg2: T2, arg3: T3, arg4: T4, callback: (err: NodeJS.ErrnoException | null, result: TResult) => void) => void; export function callbackify( fn: (arg1: T1, arg2: T2, arg3: T3, arg4: T4, arg5: T5) => Promise ): (arg1: T1, arg2: T2, arg3: T3, arg4: T4, arg5: T5, callback: (err: NodeJS.ErrnoException) => void) => void; export function callbackify( fn: (arg1: T1, arg2: T2, arg3: T3, arg4: T4, arg5: T5) => Promise ): (arg1: T1, arg2: T2, arg3: T3, arg4: T4, arg5: T5, callback: (err: NodeJS.ErrnoException | null, result: TResult) => void) => void; export function callbackify( fn: (arg1: T1, arg2: T2, arg3: T3, arg4: T4, arg5: T5, arg6: T6) => Promise ): (arg1: T1, arg2: T2, arg3: T3, arg4: T4, arg5: T5, arg6: T6, callback: (err: NodeJS.ErrnoException) => void) => void; export function callbackify( fn: (arg1: T1, arg2: T2, arg3: T3, arg4: T4, arg5: T5, arg6: T6) => Promise ): (arg1: T1, arg2: T2, arg3: T3, arg4: T4, arg5: T5, arg6: T6, callback: (err: NodeJS.ErrnoException | null, result: TResult) => void) => void; export interface CustomPromisifyLegacy extends Function { __promisify__: TCustom; } export interface CustomPromisifySymbol extends Function { [promisify.custom]: TCustom; } export type CustomPromisify = CustomPromisifySymbol | CustomPromisifyLegacy; /** * Takes a function following the common error-first callback style, i.e. taking * an `(err, value) => ...` callback as the last argument, and returns a version * that returns promises. * * ```js * const util = require('util'); * const fs = require('fs'); * * const stat = util.promisify(fs.stat); * stat('.').then((stats) => { * // Do something with `stats` * }).catch((error) => { * // Handle the error. * }); * ``` * * Or, equivalently using `async function`s: * * ```js * const util = require('util'); * const fs = require('fs'); * * const stat = util.promisify(fs.stat); * * async function callStat() { * const stats = await stat('.'); * console.log(`This directory is owned by ${stats.uid}`); * } * ``` * * If there is an `original[util.promisify.custom]` property present, `promisify`will return its value, see `Custom promisified functions`. * * `promisify()` assumes that `original` is a function taking a callback as its * final argument in all cases. If `original` is not a function, `promisify()`will throw an error. If `original` is a function but its last argument is not * an error-first callback, it will still be passed an error-first * callback as its last argument. * * Using `promisify()` on class methods or other methods that use `this` may not * work as expected unless handled specially: * * ```js * const util = require('util'); * * class Foo { * constructor() { * this.a = 42; * } * * bar(callback) { * callback(null, this.a); * } * } * * const foo = new Foo(); * * const naiveBar = util.promisify(foo.bar); * // TypeError: Cannot read property 'a' of undefined * // naiveBar().then(a => console.log(a)); * * naiveBar.call(foo).then((a) => console.log(a)); // '42' * * const bindBar = naiveBar.bind(foo); * bindBar().then((a) => console.log(a)); // '42' * ``` * @since v8.0.0 */ export function promisify(fn: CustomPromisify): TCustom; export function promisify(fn: (callback: (err: any, result: TResult) => void) => void): () => Promise; export function promisify(fn: (callback: (err?: any) => void) => void): () => Promise; export function promisify(fn: (arg1: T1, callback: (err: any, result: TResult) => void) => void): (arg1: T1) => Promise; export function promisify(fn: (arg1: T1, callback: (err?: any) => void) => void): (arg1: T1) => Promise; export function promisify(fn: (arg1: T1, arg2: T2, callback: (err: any, result: TResult) => void) => void): (arg1: T1, arg2: T2) => Promise; export function promisify(fn: (arg1: T1, arg2: T2, callback: (err?: any) => void) => void): (arg1: T1, arg2: T2) => Promise; export function promisify(fn: (arg1: T1, arg2: T2, arg3: T3, callback: (err: any, result: TResult) => void) => void): (arg1: T1, arg2: T2, arg3: T3) => Promise; export function promisify(fn: (arg1: T1, arg2: T2, arg3: T3, callback: (err?: any) => void) => void): (arg1: T1, arg2: T2, arg3: T3) => Promise; export function promisify( fn: (arg1: T1, arg2: T2, arg3: T3, arg4: T4, callback: (err: any, result: TResult) => void) => void ): (arg1: T1, arg2: T2, arg3: T3, arg4: T4) => Promise; export function promisify(fn: (arg1: T1, arg2: T2, arg3: T3, arg4: T4, callback: (err?: any) => void) => void): (arg1: T1, arg2: T2, arg3: T3, arg4: T4) => Promise; export function promisify( fn: (arg1: T1, arg2: T2, arg3: T3, arg4: T4, arg5: T5, callback: (err: any, result: TResult) => void) => void ): (arg1: T1, arg2: T2, arg3: T3, arg4: T4, arg5: T5) => Promise; export function promisify( fn: (arg1: T1, arg2: T2, arg3: T3, arg4: T4, arg5: T5, callback: (err?: any) => void) => void ): (arg1: T1, arg2: T2, arg3: T3, arg4: T4, arg5: T5) => Promise; export function promisify(fn: Function): Function; export namespace promisify { /** * That can be used to declare custom promisified variants of functions. */ const custom: unique symbol; } /** * An implementation of the [WHATWG Encoding Standard](https://encoding.spec.whatwg.org/) `TextDecoder` API. * * ```js * const decoder = new TextDecoder(); * const u8arr = new Uint8Array([72, 101, 108, 108, 111]); * console.log(decoder.decode(u8arr)); // Hello * ``` * @since v8.3.0 */ export class TextDecoder { /** * The encoding supported by the `TextDecoder` instance. */ readonly encoding: string; /** * The value will be `true` if decoding errors result in a `TypeError` being * thrown. */ readonly fatal: boolean; /** * The value will be `true` if the decoding result will include the byte order * mark. */ readonly ignoreBOM: boolean; constructor( encoding?: string, options?: { fatal?: boolean | undefined; ignoreBOM?: boolean | undefined; } ); /** * Decodes the `input` and returns a string. If `options.stream` is `true`, any * incomplete byte sequences occurring at the end of the `input` are buffered * internally and emitted after the next call to `textDecoder.decode()`. * * If `textDecoder.fatal` is `true`, decoding errors that occur will result in a`TypeError` being thrown. * @param input An `ArrayBuffer`, `DataView` or `TypedArray` instance containing the encoded data. */ decode( input?: NodeJS.ArrayBufferView | ArrayBuffer | null, options?: { stream?: boolean | undefined; } ): string; } export interface EncodeIntoResult { /** * The read Unicode code units of input. */ read: number; /** * The written UTF-8 bytes of output. */ written: number; } export { types }; /** * An implementation of the [WHATWG Encoding Standard](https://encoding.spec.whatwg.org/) `TextEncoder` API. All * instances of `TextEncoder` only support UTF-8 encoding. * * ```js * const encoder = new TextEncoder(); * const uint8array = encoder.encode('this is some data'); * ``` * * The `TextEncoder` class is also available on the global object. * @since v8.3.0 */ export class TextEncoder { /** * The encoding supported by the `TextEncoder` instance. Always set to `'utf-8'`. */ readonly encoding: string; /** * UTF-8 encodes the `input` string and returns a `Uint8Array` containing the * encoded bytes. * @param [input='an empty string'] The text to encode. */ encode(input?: string): Uint8Array; /** * UTF-8 encodes the `src` string to the `dest` Uint8Array and returns an object * containing the read Unicode code units and written UTF-8 bytes. * * ```js * const encoder = new TextEncoder(); * const src = 'this is some data'; * const dest = new Uint8Array(10); * const { read, written } = encoder.encodeInto(src, dest); * ``` * @param src The text to encode. * @param dest The array to hold the encode result. */ encodeInto(src: string, dest: Uint8Array): EncodeIntoResult; } } declare module 'util/types' { export * from 'util/types'; } declare module 'util/types' { import { KeyObject, webcrypto } from 'node:crypto'; /** * Returns `true` if the value is a built-in [`ArrayBuffer`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer) or * [`SharedArrayBuffer`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer) instance. * * See also `util.types.isArrayBuffer()` and `util.types.isSharedArrayBuffer()`. * * ```js * util.types.isAnyArrayBuffer(new ArrayBuffer()); // Returns true * util.types.isAnyArrayBuffer(new SharedArrayBuffer()); // Returns true * ``` * @since v10.0.0 */ function isAnyArrayBuffer(object: unknown): object is ArrayBufferLike; /** * Returns `true` if the value is an `arguments` object. * * ```js * function foo() { * util.types.isArgumentsObject(arguments); // Returns true * } * ``` * @since v10.0.0 */ function isArgumentsObject(object: unknown): object is IArguments; /** * Returns `true` if the value is a built-in [`ArrayBuffer`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer) instance. * This does _not_ include [`SharedArrayBuffer`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer) instances. Usually, it is * desirable to test for both; See `util.types.isAnyArrayBuffer()` for that. * * ```js * util.types.isArrayBuffer(new ArrayBuffer()); // Returns true * util.types.isArrayBuffer(new SharedArrayBuffer()); // Returns false * ``` * @since v10.0.0 */ function isArrayBuffer(object: unknown): object is ArrayBuffer; /** * Returns `true` if the value is an instance of one of the [`ArrayBuffer`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer) views, such as typed * array objects or [`DataView`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView). Equivalent to * [`ArrayBuffer.isView()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer/isView). * * ```js * util.types.isArrayBufferView(new Int8Array()); // true * util.types.isArrayBufferView(Buffer.from('hello world')); // true * util.types.isArrayBufferView(new DataView(new ArrayBuffer(16))); // true * util.types.isArrayBufferView(new ArrayBuffer()); // false * ``` * @since v10.0.0 */ function isArrayBufferView(object: unknown): object is NodeJS.ArrayBufferView; /** * Returns `true` if the value is an [async function](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function). * This only reports back what the JavaScript engine is seeing; * in particular, the return value may not match the original source code if * a transpilation tool was used. * * ```js * util.types.isAsyncFunction(function foo() {}); // Returns false * util.types.isAsyncFunction(async function foo() {}); // Returns true * ``` * @since v10.0.0 */ function isAsyncFunction(object: unknown): boolean; /** * Returns `true` if the value is a `BigInt64Array` instance. * * ```js * util.types.isBigInt64Array(new BigInt64Array()); // Returns true * util.types.isBigInt64Array(new BigUint64Array()); // Returns false * ``` * @since v10.0.0 */ function isBigInt64Array(value: unknown): value is BigInt64Array; /** * Returns `true` if the value is a `BigUint64Array` instance. * * ```js * util.types.isBigUint64Array(new BigInt64Array()); // Returns false * util.types.isBigUint64Array(new BigUint64Array()); // Returns true * ``` * @since v10.0.0 */ function isBigUint64Array(value: unknown): value is BigUint64Array; /** * Returns `true` if the value is a boolean object, e.g. created * by `new Boolean()`. * * ```js * util.types.isBooleanObject(false); // Returns false * util.types.isBooleanObject(true); // Returns false * util.types.isBooleanObject(new Boolean(false)); // Returns true * util.types.isBooleanObject(new Boolean(true)); // Returns true * util.types.isBooleanObject(Boolean(false)); // Returns false * util.types.isBooleanObject(Boolean(true)); // Returns false * ``` * @since v10.0.0 */ function isBooleanObject(object: unknown): object is Boolean; /** * Returns `true` if the value is any boxed primitive object, e.g. created * by `new Boolean()`, `new String()` or `Object(Symbol())`. * * For example: * * ```js * util.types.isBoxedPrimitive(false); // Returns false * util.types.isBoxedPrimitive(new Boolean(false)); // Returns true * util.types.isBoxedPrimitive(Symbol('foo')); // Returns false * util.types.isBoxedPrimitive(Object(Symbol('foo'))); // Returns true * util.types.isBoxedPrimitive(Object(BigInt(5))); // Returns true * ``` * @since v10.11.0 */ function isBoxedPrimitive(object: unknown): object is String | Number | BigInt | Boolean | Symbol; /** * Returns `true` if the value is a built-in [`DataView`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView) instance. * * ```js * const ab = new ArrayBuffer(20); * util.types.isDataView(new DataView(ab)); // Returns true * util.types.isDataView(new Float64Array()); // Returns false * ``` * * See also [`ArrayBuffer.isView()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer/isView). * @since v10.0.0 */ function isDataView(object: unknown): object is DataView; /** * Returns `true` if the value is a built-in [`Date`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date) instance. * * ```js * util.types.isDate(new Date()); // Returns true * ``` * @since v10.0.0 */ function isDate(object: unknown): object is Date; /** * Returns `true` if the value is a native `External` value. * * A native `External` value is a special type of object that contains a * raw C++ pointer (`void*`) for access from native code, and has no other * properties. Such objects are created either by Node.js internals or native * addons. In JavaScript, they are [frozen](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/freeze) objects with a`null` prototype. * * ```c * #include * #include * napi_value result; * static napi_value MyNapi(napi_env env, napi_callback_info info) { * int* raw = (int*) malloc(1024); * napi_status status = napi_create_external(env, (void*) raw, NULL, NULL, &result); * if (status != napi_ok) { * napi_throw_error(env, NULL, "napi_create_external failed"); * return NULL; * } * return result; * } * ... * DECLARE_NAPI_PROPERTY("myNapi", MyNapi) * ... * ``` * * ```js * const native = require('napi_addon.node'); * const data = native.myNapi(); * util.types.isExternal(data); // returns true * util.types.isExternal(0); // returns false * util.types.isExternal(new String('foo')); // returns false * ``` * * For further information on `napi_create_external`, refer to `napi_create_external()`. * @since v10.0.0 */ function isExternal(object: unknown): boolean; /** * Returns `true` if the value is a built-in [`Float32Array`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float32Array) instance. * * ```js * util.types.isFloat32Array(new ArrayBuffer()); // Returns false * util.types.isFloat32Array(new Float32Array()); // Returns true * util.types.isFloat32Array(new Float64Array()); // Returns false * ``` * @since v10.0.0 */ function isFloat32Array(object: unknown): object is Float32Array; /** * Returns `true` if the value is a built-in [`Float64Array`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float64Array) instance. * * ```js * util.types.isFloat64Array(new ArrayBuffer()); // Returns false * util.types.isFloat64Array(new Uint8Array()); // Returns false * util.types.isFloat64Array(new Float64Array()); // Returns true * ``` * @since v10.0.0 */ function isFloat64Array(object: unknown): object is Float64Array; /** * Returns `true` if the value is a generator function. * This only reports back what the JavaScript engine is seeing; * in particular, the return value may not match the original source code if * a transpilation tool was used. * * ```js * util.types.isGeneratorFunction(function foo() {}); // Returns false * util.types.isGeneratorFunction(function* foo() {}); // Returns true * ``` * @since v10.0.0 */ function isGeneratorFunction(object: unknown): object is GeneratorFunction; /** * Returns `true` if the value is a generator object as returned from a * built-in generator function. * This only reports back what the JavaScript engine is seeing; * in particular, the return value may not match the original source code if * a transpilation tool was used. * * ```js * function* foo() {} * const generator = foo(); * util.types.isGeneratorObject(generator); // Returns true * ``` * @since v10.0.0 */ function isGeneratorObject(object: unknown): object is Generator; /** * Returns `true` if the value is a built-in [`Int8Array`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int8Array) instance. * * ```js * util.types.isInt8Array(new ArrayBuffer()); // Returns false * util.types.isInt8Array(new Int8Array()); // Returns true * util.types.isInt8Array(new Float64Array()); // Returns false * ``` * @since v10.0.0 */ function isInt8Array(object: unknown): object is Int8Array; /** * Returns `true` if the value is a built-in [`Int16Array`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int16Array) instance. * * ```js * util.types.isInt16Array(new ArrayBuffer()); // Returns false * util.types.isInt16Array(new Int16Array()); // Returns true * util.types.isInt16Array(new Float64Array()); // Returns false * ``` * @since v10.0.0 */ function isInt16Array(object: unknown): object is Int16Array; /** * Returns `true` if the value is a built-in [`Int32Array`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int32Array) instance. * * ```js * util.types.isInt32Array(new ArrayBuffer()); // Returns false * util.types.isInt32Array(new Int32Array()); // Returns true * util.types.isInt32Array(new Float64Array()); // Returns false * ``` * @since v10.0.0 */ function isInt32Array(object: unknown): object is Int32Array; /** * Returns `true` if the value is a built-in [`Map`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map) instance. * * ```js * util.types.isMap(new Map()); // Returns true * ``` * @since v10.0.0 */ function isMap(object: T | {}): object is T extends ReadonlyMap ? (unknown extends T ? never : ReadonlyMap) : Map; /** * Returns `true` if the value is an iterator returned for a built-in [`Map`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map) instance. * * ```js * const map = new Map(); * util.types.isMapIterator(map.keys()); // Returns true * util.types.isMapIterator(map.values()); // Returns true * util.types.isMapIterator(map.entries()); // Returns true * util.types.isMapIterator(map[Symbol.iterator]()); // Returns true * ``` * @since v10.0.0 */ function isMapIterator(object: unknown): boolean; /** * Returns `true` if the value is an instance of a [Module Namespace Object](https://tc39.github.io/ecma262/#sec-module-namespace-exotic-objects). * * ```js * import * as ns from './a.js'; * * util.types.isModuleNamespaceObject(ns); // Returns true * ``` * @since v10.0.0 */ function isModuleNamespaceObject(value: unknown): boolean; /** * Returns `true` if the value is an instance of a built-in `Error` type. * * ```js * util.types.isNativeError(new Error()); // Returns true * util.types.isNativeError(new TypeError()); // Returns true * util.types.isNativeError(new RangeError()); // Returns true * ``` * @since v10.0.0 */ function isNativeError(object: unknown): object is Error; /** * Returns `true` if the value is a number object, e.g. created * by `new Number()`. * * ```js * util.types.isNumberObject(0); // Returns false * util.types.isNumberObject(new Number(0)); // Returns true * ``` * @since v10.0.0 */ function isNumberObject(object: unknown): object is Number; /** * Returns `true` if the value is a built-in [`Promise`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise). * * ```js * util.types.isPromise(Promise.resolve(42)); // Returns true * ``` * @since v10.0.0 */ function isPromise(object: unknown): object is Promise; /** * Returns `true` if the value is a [`Proxy`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy) instance. * * ```js * const target = {}; * const proxy = new Proxy(target, {}); * util.types.isProxy(target); // Returns false * util.types.isProxy(proxy); // Returns true * ``` * @since v10.0.0 */ function isProxy(object: unknown): boolean; /** * Returns `true` if the value is a regular expression object. * * ```js * util.types.isRegExp(/abc/); // Returns true * util.types.isRegExp(new RegExp('abc')); // Returns true * ``` * @since v10.0.0 */ function isRegExp(object: unknown): object is RegExp; /** * Returns `true` if the value is a built-in [`Set`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set) instance. * * ```js * util.types.isSet(new Set()); // Returns true * ``` * @since v10.0.0 */ function isSet(object: T | {}): object is T extends ReadonlySet ? (unknown extends T ? never : ReadonlySet) : Set; /** * Returns `true` if the value is an iterator returned for a built-in [`Set`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set) instance. * * ```js * const set = new Set(); * util.types.isSetIterator(set.keys()); // Returns true * util.types.isSetIterator(set.values()); // Returns true * util.types.isSetIterator(set.entries()); // Returns true * util.types.isSetIterator(set[Symbol.iterator]()); // Returns true * ``` * @since v10.0.0 */ function isSetIterator(object: unknown): boolean; /** * Returns `true` if the value is a built-in [`SharedArrayBuffer`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer) instance. * This does _not_ include [`ArrayBuffer`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer) instances. Usually, it is * desirable to test for both; See `util.types.isAnyArrayBuffer()` for that. * * ```js * util.types.isSharedArrayBuffer(new ArrayBuffer()); // Returns false * util.types.isSharedArrayBuffer(new SharedArrayBuffer()); // Returns true * ``` * @since v10.0.0 */ function isSharedArrayBuffer(object: unknown): object is SharedArrayBuffer; /** * Returns `true` if the value is a string object, e.g. created * by `new String()`. * * ```js * util.types.isStringObject('foo'); // Returns false * util.types.isStringObject(new String('foo')); // Returns true * ``` * @since v10.0.0 */ function isStringObject(object: unknown): object is String; /** * Returns `true` if the value is a symbol object, created * by calling `Object()` on a `Symbol` primitive. * * ```js * const symbol = Symbol('foo'); * util.types.isSymbolObject(symbol); // Returns false * util.types.isSymbolObject(Object(symbol)); // Returns true * ``` * @since v10.0.0 */ function isSymbolObject(object: unknown): object is Symbol; /** * Returns `true` if the value is a built-in [`TypedArray`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray) instance. * * ```js * util.types.isTypedArray(new ArrayBuffer()); // Returns false * util.types.isTypedArray(new Uint8Array()); // Returns true * util.types.isTypedArray(new Float64Array()); // Returns true * ``` * * See also [`ArrayBuffer.isView()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer/isView). * @since v10.0.0 */ function isTypedArray(object: unknown): object is NodeJS.TypedArray; /** * Returns `true` if the value is a built-in [`Uint8Array`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array) instance. * * ```js * util.types.isUint8Array(new ArrayBuffer()); // Returns false * util.types.isUint8Array(new Uint8Array()); // Returns true * util.types.isUint8Array(new Float64Array()); // Returns false * ``` * @since v10.0.0 */ function isUint8Array(object: unknown): object is Uint8Array; /** * Returns `true` if the value is a built-in [`Uint8ClampedArray`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8ClampedArray) instance. * * ```js * util.types.isUint8ClampedArray(new ArrayBuffer()); // Returns false * util.types.isUint8ClampedArray(new Uint8ClampedArray()); // Returns true * util.types.isUint8ClampedArray(new Float64Array()); // Returns false * ``` * @since v10.0.0 */ function isUint8ClampedArray(object: unknown): object is Uint8ClampedArray; /** * Returns `true` if the value is a built-in [`Uint16Array`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint16Array) instance. * * ```js * util.types.isUint16Array(new ArrayBuffer()); // Returns false * util.types.isUint16Array(new Uint16Array()); // Returns true * util.types.isUint16Array(new Float64Array()); // Returns false * ``` * @since v10.0.0 */ function isUint16Array(object: unknown): object is Uint16Array; /** * Returns `true` if the value is a built-in [`Uint32Array`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint32Array) instance. * * ```js * util.types.isUint32Array(new ArrayBuffer()); // Returns false * util.types.isUint32Array(new Uint32Array()); // Returns true * util.types.isUint32Array(new Float64Array()); // Returns false * ``` * @since v10.0.0 */ function isUint32Array(object: unknown): object is Uint32Array; /** * Returns `true` if the value is a built-in [`WeakMap`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap) instance. * * ```js * util.types.isWeakMap(new WeakMap()); // Returns true * ``` * @since v10.0.0 */ function isWeakMap(object: unknown): object is WeakMap; /** * Returns `true` if the value is a built-in [`WeakSet`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakSet) instance. * * ```js * util.types.isWeakSet(new WeakSet()); // Returns true * ``` * @since v10.0.0 */ function isWeakSet(object: unknown): object is WeakSet; /** * Returns `true` if `value` is a `KeyObject`, `false` otherwise. * @since v16.2.0 */ function isKeyObject(object: unknown): object is KeyObject; /** * Returns `true` if `value` is a `CryptoKey`, `false` otherwise. * @since v16.2.0 */ function isCryptoKey(object: unknown): object is webcrypto.CryptoKey; } declare module 'node:util' { export * from 'util'; } declare module 'node:util/types' { export * from 'util/types'; }