[object Object]

Stability: 2 - Stable

These objects are available in all modules.

The following variables may appear to be global but are not. They exist only in the scope of CommonJS modules:

• __dirname
• __filename
• exports
• module
• require()

The objects listed here are specific to Node.js. There are built-in objects that are part of the JavaScript language itself, which are also globally accessible.

[object Object]

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

[object Object]

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

[object Object]

A utility class used to signal cancelation in selected Promise-based APIs. The API is based on the Web API <a href="globals.html#class-abortcontroller" class="type"><AbortController></a>.

const ac = new AbortController();

ac.signal.addEventListener('abort', () => console.log('Aborted!'),
                           { once: true });

ac.abort();

console.log(ac.signal.aborted);  // Prints true

[object Object]

• reason <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a> An optional reason, retrievable on the AbortSignal's reason property.

Triggers the abort signal, causing the abortController.signal to emit the 'abort' event.

[object Object]

• Type: <a href="globals.html#class-abortsignal" class="type"><AbortSignal></a>

[object Object]

• Extends: <a href="events.html#class-eventtarget" class="type"><EventTarget></a>

The AbortSignal is used to notify observers when the abortController.abort() method is called.

[object Object]

• reason <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a>
• Returns: <a href="globals.html#class-abortsignal" class="type"><AbortSignal></a>

Returns a new already aborted AbortSignal.

[object Object]

• delay <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#number_type" class="type"><number></a> The number of milliseconds to wait before triggering the AbortSignal.

Returns a new AbortSignal which will be aborted in delay milliseconds.

[object Object]

• signals <a href="globals.html#class-abortsignal" class="type"><AbortSignal[]></a> The AbortSignals of which to compose a new AbortSignal.

Returns a new AbortSignal which will be aborted if any of the provided signals are aborted. Its abortSignal.reason will be set to whichever one of the signals caused it to be aborted.

[object Object]

The 'abort' event is emitted when the abortController.abort() method is called. The callback is invoked with a single object argument with a single type property set to 'abort':

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();

The AbortController with which the AbortSignal is associated will only ever trigger the 'abort' event once. We recommended that code check that the abortSignal.aborted attribute is false before adding an 'abort' event listener.

Any event listeners attached to the AbortSignal should use the { once: true } option (or, if using the EventEmitter APIs to attach a listener, use the once() method) to ensure that the event listener is removed as soon as the 'abort' event is handled. Failure to do so may result in memory leaks.

[object Object]

• Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#boolean_type" class="type"><boolean></a>

True after the AbortController has been aborted.

[object Object]

• Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a>

An optional callback function that may be set by user code to be notified when the abortController.abort() function has been called.

[object Object]

• Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types" class="type"><any></a>

An optional reason specified when the AbortSignal was triggered.

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

[object Object]

If abortSignal.aborted is true, throws abortSignal.reason.

[object Object]

Stability: 3 - Legacy. Use Buffer.from(data, 'base64') instead.

Global alias for buffer.atob().

An automated migration is available (source):

npx codemod@latest @nodejs/buffer-atob-btoa

[object Object]

See <a href="buffer.html#class-blob" class="type"><Blob></a>.

[object Object]

See <a href="worker_threads.html#class-broadcastchannel-extends-eventtarget" class="type"><BroadcastChannel></a>.

[object Object]

Stability: 3 - Legacy. Use buf.toString('base64') instead.

Global alias for buffer.btoa().

An automated migration is available (source):

npx codemod@latest @nodejs/buffer-atob-btoa

[object Object]

• Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a>

Used to handle binary data. See the buffer section.

[object Object]

A browser-compatible implementation of ByteLengthQueuingStrategy.

[object Object]

clearImmediate is described in the timers section.

[object Object]

clearInterval is described in the timers section.

[object Object]

clearTimeout is described in the timers section.

[object Object]

A browser-compatible implementation of <a href="https://developer.mozilla.org/en-US/docs/Web/API/CloseEvent" class="type"><CloseEvent></a>. Disable this API with the --no-experimental-websocket CLI flag.

[object Object]

A browser-compatible implementation of CompressionStream.

[object Object]

• Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a>

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

[object Object]

A browser-compatible implementation of CountQueuingStrategy.

[object Object]

A browser-compatible implementation of <a href="webcrypto.html#class-crypto" class="type"><Crypto></a>. This global is available only if the Node.js binary was compiled with including support for the node:crypto module.

[object Object]

A browser-compatible implementation of the Web Crypto API.

[object Object]

A browser-compatible implementation of <a href="webcrypto.html#class-cryptokey" class="type"><CryptoKey></a>. This global is available only if the Node.js binary was compiled with including support for the node:crypto module.

[object Object]

A browser-compatible implementation of <a href="events.html#class-customevent" class="type"><CustomEvent></a>.

[object Object]

A browser-compatible implementation of DecompressionStream.

[object Object]

The WHATWG <a href="https://developer.mozilla.org/en-US/docs/Web/API/DOMException" class="type"><DOMException></a> class.

[object Object]

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

[object Object]

Stability: 1 - Experimental. Enable this API with the --experimental-eventsource CLI flag.

A browser-compatible implementation of <a href="https://developer.mozilla.org/en-US/docs/Web/API/EventSource" class="type"><EventSource></a>.

[object Object]

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

[object Object]

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

[object Object]

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);
}

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.

[object Object]

You can use a custom dispatcher to dispatch requests passing it in fetch's options object. The dispatcher must be compatible with undici's Dispatcher class.

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

It is possible to change the global dispatcher in Node.js by installing undici and using the setGlobalDispatcher() method. Calling this method will affect both undici and Node.js.

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

[object Object]

The following globals are available to use with fetch:

• FormData
• Headers
• Request
• Response

[object Object]

See <a href="buffer.html#class-file" class="type"><File></a>.

[object Object]

A browser-compatible implementation of <a href="https://developer.mozilla.org/en-US/docs/Web/API/FormData" class="type"><FormData></a>.

[object Object]

Stability: 3 - Legacy. Use globalThis instead.

• Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> 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.

[object Object]

A browser-compatible implementation of <a href="https://developer.mozilla.org/en-US/docs/Web/API/Headers" class="type"><Headers></a>.

[object Object]

Stability: 1.2 - Release candidate. Enable this API with --experimental-webstorage.

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. 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.

[object Object]

The MessageChannel class. See MessageChannel for more details.

[object Object]

A browser-compatible implementation of <a href="https://developer.mozilla.org/en-US/docs/Web/API/MessageEvent" class="type"><MessageEvent></a>.

[object Object]

The MessagePort class. See MessagePort for more details.

[object Object]

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

[object Object]

Stability: 1.1 - Active development. Disable this API with the --no-experimental-global-navigator CLI flag.

A partial implementation of the Navigator API.

[object Object]

Stability: 1.1 - Active development. Disable this API with the --no-experimental-global-navigator CLI flag.

A partial implementation of window.navigator.

[object Object]

• Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#number_type" class="type"><number></a>

The navigator.hardwareConcurrency read-only property returns the number of logical processors available to the current Node.js instance.

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

[object Object]

• Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#string_type" class="type"><string></a>

The navigator.language read-only property returns a string representing the preferred language of the Node.js instance. The language will be determined by the ICU library used by Node.js at runtime based on the default language of the operating system.

The value is representing the language version as defined in RFC 5646.

The fallback value on builds without ICU is 'en-US'.

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

[object Object]

• Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#string_type" class="type"><string[]></a>

The navigator.languages read-only property returns an array of strings representing the preferred languages of the Node.js instance. By default navigator.languages contains only the value of navigator.language, which will be determined by the ICU library used by Node.js at runtime based on the default language of the operating system.

The fallback value on builds without ICU is ['en-US'].

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

[object Object]

Stability: 1 - Experimental

The navigator.locks read-only property returns a LockManager instance that can be used to coordinate access to resources that may be shared across multiple threads within the same process. This global implementation matches the semantics of the browser LockManager API.

// 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');
});

See worker_threads.locks for detailed API documentation.

[object Object]

• Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#string_type" class="type"><string></a>

The navigator.platform read-only property returns a string identifying the platform on which the Node.js instance is running.

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

[object Object]

• Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#string_type" class="type"><string></a>

The navigator.userAgent read-only property returns user agent consisting of the runtime name and major version number.

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

[object Object]

The perf_hooks.performance object.

[object Object]

The PerformanceEntry class. See PerformanceEntry for more details.

[object Object]

The PerformanceMark class. See PerformanceMark for more details.

[object Object]

The PerformanceMeasure class. See PerformanceMeasure for more details.

[object Object]

The PerformanceObserver class. See PerformanceObserver for more details.

[object Object]

The PerformanceObserverEntryList class. See PerformanceObserverEntryList for more details.

[object Object]

The PerformanceResourceTiming class. See PerformanceResourceTiming for more details.

[object Object]

• Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a>

The process object. See the process object section.

[object Object]

• callback <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> 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);
};

[object Object]

A browser-compatible implementation of ReadableByteStreamController.

[object Object]

A browser-compatible implementation of ReadableStream.

[object Object]

A browser-compatible implementation of ReadableStreamBYOBReader.

[object Object]

A browser-compatible implementation of ReadableStreamBYOBRequest.

[object Object]

A browser-compatible implementation of ReadableStreamDefaultController.

[object Object]

A browser-compatible implementation of ReadableStreamDefaultReader.

[object Object]

A browser-compatible implementation of <a href="https://developer.mozilla.org/en-US/docs/Web/API/Request" class="type"><Request></a>.

[object Object]

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

[object Object]

A browser-compatible implementation of <a href="https://developer.mozilla.org/en-US/docs/Web/API/Response" class="type"><Response></a>.

[object Object]

Stability: 1.2 - Release candidate. Enable this API with --experimental-webstorage.

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.

[object Object]

setImmediate is described in the timers section.

[object Object]

setInterval is described in the timers section.

[object Object]

setTimeout is described in the timers section.

[object Object]

Stability: 1.2 - Release candidate. Enable this API with --experimental-webstorage.

A browser-compatible implementation of <a href="https://developer.mozilla.org/en-US/docs/Web/API/Storage" class="type"><Storage></a>.

[object Object]

The WHATWG structuredClone method.

[object Object]

A browser-compatible implementation of <a href="webcrypto.html#class-subtlecrypto" class="type"><SubtleCrypto></a>. This global is available only if the Node.js binary was compiled with including support for the node:crypto module.

[object Object]

The WHATWG TextDecoder class. See the TextDecoder section.

[object Object]

A browser-compatible implementation of TextDecoderStream.

[object Object]

The WHATWG TextEncoder class. See the TextEncoder section.

[object Object]

A browser-compatible implementation of TextEncoderStream.

[object Object]

A browser-compatible implementation of TransformStream.

[object Object]

A browser-compatible implementation of TransformStreamDefaultController.

[object Object]

The WHATWG URL class. See the URL section.

[object Object]

Stability: 1 - Experimental

The WHATWG URLPattern class. See the URLPattern section.

[object Object]

The WHATWG URLSearchParams class. See the URLSearchParams section.

[object Object]

• Type: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a>

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

[object Object]

A browser-compatible implementation of <a href="https://developer.mozilla.org/en-US/docs/Web/API/WebSocket" class="type"><WebSocket></a>. Disable this API with the --no-experimental-websocket CLI flag.

[object Object]

A browser-compatible implementation of WritableStream.

[object Object]

A browser-compatible implementation of WritableStreamDefaultController.

[object Object]

A browser-compatible implementation of WritableStreamDefaultWriter.