Node.js v25.0.0 documentation

Class: AbortController#

A utility class used to signal cancelation in selected Promise-based APIs. The API is based on the Web API <AbortController>.

const ac = new AbortController();
ac.signal.addEventListener('abort', () => console.log('Aborted!'),
 { once: true });
ac.abort();
console.log(ac.signal.aborted); // Prints true copy

const ac = new AbortController();
// Use either the onabort property...
ac.signal.onabort = () => console.log('aborted!');
// Or the EventTarget API...
ac.signal.addEventListener('abort', (event) => {
 console.log(event.type); // Prints 'abort'
}, { once: true });
ac.abort(); copy

const ac = new AbortController();
ac.abort(new Error('boom!'));
console.log(ac.signal.reason); // Error: boom! copy

Class: Blob#

See <Blob>.

Class: Buffer#

• Type: <Function>

Used to handle binary data. See the buffer section.

Class: ByteLengthQueuingStrategy#

A browser-compatible implementation of ByteLengthQueuingStrategy.

__dirname#

This variable may appear to be global but is not. See __dirname.

__filename#

This variable may appear to be global but is not. See __filename.

atob(data)#

Global alias for buffer.atob().

Class: BroadcastChannel#

See <BroadcastChannel>.

btoa(data)#

Global alias for buffer.btoa().

clearImmediate(immediateObject)#

clearImmediate is described in the timers section.

clearInterval(intervalObject)#

clearInterval is described in the timers section.

clearTimeout(timeoutObject)#

clearTimeout is described in the timers section.

Class: CloseEvent#

A browser-compatible implementation of <CloseEvent>. Disable this API with the --no-experimental-websocket CLI flag.

Class: CompressionStream#

A browser-compatible implementation of CompressionStream.

console#

• Type: <Object>

Used to print to stdout and stderr. See the console section.

Class: CountQueuingStrategy#

A browser-compatible implementation of CountQueuingStrategy.

Class: Crypto#

A browser-compatible implementation of <Crypto>. This global is available only if the Node.js binary was compiled with including support for the node:crypto module.

crypto#

A browser-compatible implementation of the Web Crypto API.

Class: CryptoKey#

A browser-compatible implementation of <CryptoKey>. This global is available only if the Node.js binary was compiled with including support for the node:crypto module.

Class: CustomEvent#

A browser-compatible implementation of <CustomEvent>.

Class: DecompressionStream#

A browser-compatible implementation of DecompressionStream.

ErrorEvent#

A browser-compatible implementation of <ErrorEvent>.

Class: Event#

A browser-compatible implementation of the Event class. See EventTarget and Event API for more details.

Class: EventSource#

A browser-compatible implementation of <EventSource>.

Class: EventTarget#

A browser-compatible implementation of the EventTarget class. See EventTarget and Event API for more details.

exports#

This variable may appear to be global but is not. See exports.

fetch#

A browser-compatible implementation of the fetch() function.

const res = await fetch('https://nodejs.org/api/documentation.json');
if (res.ok) {
 const data = await res.json();
 console.log(data);
} copy

The implementation is based upon undici, an HTTP/1.1 client written from scratch for Node.js. You can figure out which version of undici is bundled in your Node.js process reading the process.versions.undici property.

fetch(url, { dispatcher: new MyAgent() }); copy

import { setGlobalDispatcher } from 'undici';
setGlobalDispatcher(new MyAgent()); copy

Class: File#

See <File>.

Class: FormData#

A browser-compatible implementation of <FormData>.

global#

• Type: <Object> The global namespace object.

In browsers, the top-level scope has traditionally been the global scope. This means that var something will define a new global variable, except within ECMAScript modules. In Node.js, this is different. The top-level scope is not the global scope; var something inside a Node.js module will be local to that module, regardless of whether it is a CommonJS module or an ECMAScript module.

Class: Headers#

A browser-compatible implementation of <Headers>.

localStorage#

A browser-compatible implementation of localStorage. Data is stored unencrypted in the file specified by the --localstorage-file CLI flag. The maximum amount of data that can be stored is 10 MB. Any modification of this data outside of the Web Storage API is not supported. Disable this API with the --no-webstorage (or its alias --no-experimental-webstorage) CLI flag. localStorage data is not stored per user or per request when used in the context of a server, it is shared across all users and requests.

Class: MessageChannel#

The MessageChannel class. See MessageChannel for more details.

Class: MessageEvent#

A browser-compatible implementation of <MessageEvent>.

Class: MessagePort#

The MessagePort class. See MessagePort for more details.

module#

This variable may appear to be global but is not. See module.

Class: Navigator#

A partial implementation of the Navigator API.

navigator#

A partial implementation of window.navigator.

console.log(`This process is running on ${navigator.hardwareConcurrency} logical processors`); copy

console.log(`The preferred language of the Node.js instance has the tag '${navigator.language}'`); copy

console.log(`The preferred languages are '${navigator.languages}'`); copy

console.log(`This process is running on ${navigator.platform}`); copy

console.log(`The user-agent is ${navigator.userAgent}`); // Prints "Node.js/21" copy

// Request an exclusive lock
await navigator.locks.request('my_resource', async (lock) => {
 // The lock has been acquired.
 console.log(`Lock acquired: ${lock.name}`);
 // Lock is automatically released when the function returns
});
// Request a shared lock
await navigator.locks.request('shared_resource', { mode: 'shared' }, async (lock) => {
 // Multiple shared locks can be held simultaneously
 console.log(`Shared lock acquired: ${lock.name}`);
});// Request an exclusive lock
navigator.locks.request('my_resource', async (lock) => {
 // The lock has been acquired.
 console.log(`Lock acquired: ${lock.name}`);
 // Lock is automatically released when the function returns
}).then(() => {
 console.log('Lock released');
});
// Request a shared lock
navigator.locks.request('shared_resource', { mode: 'shared' }, async (lock) => {
 // Multiple shared locks can be held simultaneously
 console.log(`Shared lock acquired: ${lock.name}`);
}).then(() => {
 console.log('Shared lock released');
});copy

Class: PerformanceEntry#

The PerformanceEntry class. See PerformanceEntry for more details.

Class: PerformanceMark#

The PerformanceMark class. See PerformanceMark for more details.

Class: PerformanceMeasure#

The PerformanceMeasure class. See PerformanceMeasure for more details.

Class: PerformanceObserver#

The PerformanceObserver class. See PerformanceObserver for more details.

Class: PerformanceObserverEntryList#

The PerformanceObserverEntryList class. See PerformanceObserverEntryList for more details.

Class: PerformanceResourceTiming#

The PerformanceResourceTiming class. See PerformanceResourceTiming for more details.

performance#

The perf_hooks.performance object.

process#

• Type: <Object>

The process object. See the process object section.

queueMicrotask(callback)#

• callback <Function> Function to be queued.

The queueMicrotask() method queues a microtask to invoke callback. If callback throws an exception, the process object 'uncaughtException' event will be emitted.

The microtask queue is managed by V8 and may be used in a similar manner to the process.nextTick() queue, which is managed by Node.js. The process.nextTick() queue is always processed before the microtask queue within each turn of the Node.js event loop.

// Here, `queueMicrotask()` is used to ensure the 'load' event is always
// emitted asynchronously, and therefore consistently. Using
// `process.nextTick()` here would result in the 'load' event always emitting
// before any other promise jobs.
DataHandler.prototype.load = async function load(key) {
 const hit = this._cache.get(key);
 if (hit !== undefined) {
 queueMicrotask(() => {
 this.emit('load', hit);
 });
 return;
 }
 const data = await fetchData(key);
 this._cache.set(key, data);
 this.emit('load', data);
}; copy

Class: ReadableByteStreamController#

A browser-compatible implementation of ReadableByteStreamController.

Class: ReadableStream#

A browser-compatible implementation of ReadableStream.

Class: ReadableStreamBYOBReader#

A browser-compatible implementation of ReadableStreamBYOBReader.

Class: ReadableStreamBYOBRequest#

A browser-compatible implementation of ReadableStreamBYOBRequest.

Class: ReadableStreamDefaultController#

A browser-compatible implementation of ReadableStreamDefaultController.

Class: ReadableStreamDefaultReader#

A browser-compatible implementation of ReadableStreamDefaultReader.

require()#

This variable may appear to be global but is not. See require().

Class: Response#

A browser-compatible implementation of <Response>.

Class: Request#

A browser-compatible implementation of <Request>.

sessionStorage#

A browser-compatible implementation of sessionStorage. Data is stored in memory, with a storage quota of 10 MB. sessionStorage data persists only within the currently running process, and is not shared between workers.

setImmediate(callback[, ...args])#

setImmediate is described in the timers section.

setInterval(callback, delay[, ...args])#

setInterval is described in the timers section.

setTimeout(callback, delay[, ...args])#

setTimeout is described in the timers section.

Class: Storage#

A browser-compatible implementation of <Storage>. Disable this API with the --no-webstorage (or its alias --no-experimental-webstorage) CLI flag.

structuredClone(value[, options])#

The WHATWG structuredClone method.

Class: SubtleCrypto#

A browser-compatible implementation of <SubtleCrypto>. This global is available only if the Node.js binary was compiled with including support for the node:crypto module.

Class: DOMException#

The WHATWG <DOMException> class.

Class: TextDecoder#

The WHATWG TextDecoder class. See the TextDecoder section.

Class: TextDecoderStream#

A browser-compatible implementation of TextDecoderStream.

Class: TextEncoder#

The WHATWG TextEncoder class. See the TextEncoder section.

Class: TextEncoderStream#

A browser-compatible implementation of TextEncoderStream.

Class: TransformStream#

A browser-compatible implementation of TransformStream.

Class: TransformStreamDefaultController#

A browser-compatible implementation of TransformStreamDefaultController.

Class: URL#

The WHATWG URL class. See the URL section.

Class: URLPattern#

The WHATWG URLPattern class. See the URLPattern section.

Class: URLSearchParams#

The WHATWG URLSearchParams class. See the URLSearchParams section.

Class: WebAssembly#

• Type: <Object>

The object that acts as the namespace for all W3C WebAssembly related functionality. See the Mozilla Developer Network for usage and compatibility.

Class: WebSocket#

A browser-compatible implementation of <WebSocket>. Disable this API with the --no-experimental-websocket CLI flag.

Class: WritableStream#

A browser-compatible implementation of WritableStream.

Class: WritableStreamDefaultController#

A browser-compatible implementation of WritableStreamDefaultController.

Class: WritableStreamDefaultWriter#

A browser-compatible implementation of WritableStreamDefaultWriter.