node/doc/api/globals.md
RafaelGSS 9e633f94ce
2026-05-05, Version 26.0.0 (Current)
assert:
  * (SEMVER-MAJOR) allow printf-style messages as assertion error (Ruben Bridgewater) https://github.com/nodejs/node/pull/58849
build:
  * (SEMVER-MAJOR) bump GCC requirement to 13.2 (Michaël Zasso) https://github.com/nodejs/node/pull/62555
  * (SEMVER-MAJOR) enable Temporal by default (Richard Lau) https://github.com/nodejs/node/pull/61806
  * (SEMVER-MAJOR) enable V8_VERIFY_WRITE_BARRIERS in debug build (Joyee Cheung) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) reset embedder string to "-node.0" (Michaël Zasso) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) target Power 9 for AIX/IBM i (Richard Lau) https://github.com/nodejs/node/pull/62296
  * (SEMVER-MAJOR) drop support for Python 3.9 (Mike McCready) https://github.com/nodejs/node/pull/61177
  * (SEMVER-MAJOR) enable maglev for Linux on s390x (Richard Lau) https://github.com/nodejs/node/pull/60863
  * (SEMVER-MAJOR) reset embedder string to "-node.0" (Michaël Zasso) https://github.com/nodejs/node/pull/60488
  * (SEMVER-MAJOR) reset embedder string to "-node.0" (Michaël Zasso) https://github.com/nodejs/node/pull/60111
build,test:
  * (CVE-2026-21717) (SEMVER-MAJOR) test array index hash collision (Joyee Cheung) https://github.com/nodejs/node/pull/61898
build,win:
  * (SEMVER-MAJOR) fix Temporal build (StefanStojanovic) https://github.com/nodejs/node/pull/61806
crypto:
  * (SEMVER-MAJOR) unify asymmetric key import through KeyObjectHandle::Init (Filip Skokan) https://github.com/nodejs/node/pull/62499
  * (SEMVER-MAJOR) runtime-deprecate DEP0203 and DEP0204 (Filip Skokan) https://github.com/nodejs/node/pull/62453
  * (SEMVER-MAJOR) decorate async crypto job errors with OpenSSL error details (Filip Skokan) https://github.com/nodejs/node/pull/62348
  * (SEMVER-MAJOR) default ML-KEM and ML-DSA pkcs8 export to seed-only format (Filip Skokan) https://github.com/nodejs/node/pull/62178
  * (SEMVER-MAJOR) move DEP0182 to End-of-Life (Tobias Nießen) https://github.com/nodejs/node/pull/61084
  * (SEMVER-MAJOR) fix DOMException name for non-extractable key error (Filip Skokan) https://github.com/nodejs/node/pull/60830
deps:
  * (SEMVER-MAJOR) V8: cherry-pick 0f024d4e66e0 (ishabi) https://github.com/nodejs/node/pull/62408
  * (SEMVER-MAJOR) fix V8 race condition for AIX (Abdirahim Musse) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) V8: cherry-pick cd2c216e7658 (LuYahan) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) V8: backport 088b7112e7ab (Igor Sheludko) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) V8: cherry-pick 00f6e834029f (Joyee Cheung) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) V8: backport bef0d9c1bc90 (Joyee Cheung) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) V8: cherry-pick cf1bce40a5ef (Richard Lau) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) V8: cherry-pick daf4656ba85e (Milad Fa) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) V8: cherry-pick d83f479604c8 (Joyee Cheung) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) V8: cherry-pick edeb0a4fa181 (Joyee Cheung) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) V8: cherry-pick aa0b288f87cc (Richard Lau) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) patch V8 to fix Windows build (StefanStojanovic) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) V8: cherry-pick highway@989a498fdf3 (Richard Lau) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) support madvise(3C) across ALL illumos revisions (Dan McDonald) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) patch V8 for illumos (Dan McDonald) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) remove problematic comment from v8-internal (Michaël Zasso) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) define V8_PRESERVE_MOST as no-op on Windows (Stefan Stojanovic) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) patch V8 to avoid duplicated zlib symbol (Michaël Zasso) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) update V8 to 14.6.202.33 (Michaël Zasso) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) update undici to 8.0.2 (Node.js GitHub Bot) https://github.com/nodejs/node/pull/62384
  * (SEMVER-MAJOR) V8: backport 151d0a44a1b2 (Abdirahim Musse) https://github.com/nodejs/node/pull/60488
  * (SEMVER-MAJOR) V8: cherry-pick 47800791b35c (Jakob Kummerow) https://github.com/nodejs/node/pull/60488
  * (SEMVER-MAJOR) patch V8 for illumos (Dan McDonald) https://github.com/nodejs/node/pull/59805
  * (SEMVER-MAJOR) use std::map in MSVC STL for EphemeronRememberedSet (Joyee Cheung) https://github.com/nodejs/node/pull/58070
  * (SEMVER-MAJOR) remove problematic comment from v8-internal (Michaël Zasso) https://github.com/nodejs/node/pull/58070
  * (SEMVER-MAJOR) patch V8 to avoid duplicated zlib symbol (Michaël Zasso) https://github.com/nodejs/node/pull/54077
  * (SEMVER-MAJOR) update V8 to 14.3.127.12 (Michaël Zasso) https://github.com/nodejs/node/pull/60488
  * (SEMVER-MAJOR) V8: cherry-pick ff34ae20c8e3 (Chengzhong Wu) https://github.com/nodejs/node/pull/60111
  * (SEMVER-MAJOR) V8: backport fed47445bbdd (Abdirahim Musse) https://github.com/nodejs/node/pull/60111
  * (SEMVER-MAJOR) patch V8 for illumos (Dan McDonald) https://github.com/nodejs/node/pull/59805
  * (SEMVER-MAJOR) use std::map in MSVC STL for EphemeronRememberedSet (Joyee Cheung) https://github.com/nodejs/node/pull/58070
  * (SEMVER-MAJOR) remove problematic comment from v8-internal (Michaël Zasso) https://github.com/nodejs/node/pull/58070
  * (SEMVER-MAJOR) patch V8 to avoid duplicated zlib symbol (Michaël Zasso) https://github.com/nodejs/node/pull/54077
  * (SEMVER-MAJOR) update V8 to 14.2.231.9 (Michaël Zasso) https://github.com/nodejs/node/pull/60111
diagnostics_channel:
  * (SEMVER-MAJOR) ensure tracePromise consistency with non-Promises (René) https://github.com/nodejs/node/pull/61766
doc:
  * (SEMVER-MAJOR) remove extensionless CJS exception for type:module packages (Matteo Collina) https://github.com/nodejs/node/pull/62176
  * (SEMVER-MAJOR) update supported Windows SDK version to 11 (Mike McCready) https://github.com/nodejs/node/pull/61973
  * (SEMVER-MAJOR) drop p8 and z13 support (Milad Fa) https://github.com/nodejs/node/pull/61005
http:
  * (SEMVER-MAJOR) move writeHeader to end-of-life (Sebastian Beltran) https://github.com/nodejs/node/pull/60635
  * (SEMVER-MAJOR) fix handling of HTTP upgrades with bodies (Tim Perry) https://github.com/nodejs/node/pull/60016
lib:
  * (SEMVER-MAJOR) return undefined for localStorage without file (Matteo Collina) https://github.com/nodejs/node/pull/61333
lib,src:
  * (SEMVER-MAJOR) implement QuotaExceededError as DOMException-derived interface (Filip Skokan) https://github.com/nodejs/node/pull/62293
module:
  * (SEMVER-MAJOR) runtime-deprecate module.register() (Geoffrey Booth) https://github.com/nodejs/node/pull/62401
  * (SEMVER-MAJOR) remove --experimental-transform-types (Marco Ippolito) https://github.com/nodejs/node/pull/61803
src:
  * (SEMVER-MAJOR) replace uses of deprecated v8::External APIs (gahaas) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) stop using `v8::PropertyCallbackInfo<T>::This()` (Igor Sheludko) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) avoid deprecated Wasm API (Clemens Backes) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) avoid deprecated `FixedArray::Get` (Clemens Backes) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) update NODE_MODULE_VERSION to 147 (Michaël Zasso) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) remove deprecated and unused isolate fields (Michaël Zasso) https://github.com/nodejs/node/pull/60488
  * (SEMVER-MAJOR) update NODE_MODULE_VERSION to 144 (Michaël Zasso) https://github.com/nodejs/node/pull/60488
  * (SEMVER-MAJOR) include `node_api_types.h` instead of `node_api.h` in `node.h` (Anna Henningsen) https://github.com/nodejs/node/pull/60496
  * (SEMVER-MAJOR) update NODE_MODULE_VERSION to 142 (Michaël Zasso) https://github.com/nodejs/node/pull/60111
stream:
  * (SEMVER-MAJOR) promote DEP0201 to runtime deprecation (René) https://github.com/nodejs/node/pull/62173
  * (SEMVER-MAJOR) move _stream_* to end-of-life (Sebastian Beltran) https://github.com/nodejs/node/pull/60657
  * (SEMVER-MAJOR) readable read one buffer at a time (Robert Nagy) https://github.com/nodejs/node/pull/60441
  * (SEMVER-MAJOR) preserve AsyncLocalStorage on finished only when needed (avcribl) https://github.com/nodejs/node/pull/59873
test:
  * (SEMVER-MAJOR) skip wasm allocation tests in workers (Michaël Zasso) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) update wpt Wasm jsapi expectations (Michaël Zasso) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) support presence of Temporal global (Michaël Zasso) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) add type tags to uses of v8::External (gahaas) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) fix test-linux-perf-logger for V8 14.3 (Michaël Zasso) https://github.com/nodejs/node/pull/60488
tools:
  * (SEMVER-MAJOR) remove v8_initializers_slow workaround from v8.gyp (Michaël Zasso) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) add Rust args to `tools/make-v8.sh` (Richard Lau) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) update V8 gypfiles for 14.6 (Michaël Zasso) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) update V8 gypfiles for 14.5 (Michaël Zasso) https://github.com/nodejs/node/pull/61898
  * (SEMVER-MAJOR) update V8 gypfiles for 14.4 (Michaël Zasso) https://github.com/nodejs/node/pull/61898
util:
  * (SEMVER-MAJOR) mark proxied objects as such when inspecting them (Ruben Bridgewater) https://github.com/nodejs/node/pull/61029
  * (SEMVER-MAJOR) reduce TextEncoder.encodeInto function size (Yagiz Nizipli) https://github.com/nodejs/node/pull/60339

PR-URL: https://github.com/nodejs/node/pull/62526
2026-05-05 11:17:12 -03:00

1432 lines
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Markdown

# Global objects
<!--introduced_in=v0.10.0-->
<!-- type=misc -->
> 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.
## `__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`][].
## Class: `AbortController`
<!-- YAML
added:
- v15.0.0
- v14.17.0
changes:
- version: v15.4.0
pr-url: https://github.com/nodejs/node/pull/35949
description: No longer experimental.
-->
A utility class used to signal cancelation in selected `Promise`-based APIs.
The API is based on the Web API {AbortController}.
```js
const ac = new AbortController();
ac.signal.addEventListener('abort', () => console.log('Aborted!'),
{ once: true });
ac.abort();
console.log(ac.signal.aborted); // Prints true
```
### `abortController.abort([reason])`
<!-- YAML
added:
- v15.0.0
- v14.17.0
changes:
- version:
- v17.2.0
- v16.14.0
pr-url: https://github.com/nodejs/node/pull/40807
description: Added the new optional reason argument.
-->
* `reason` {any} An optional reason, retrievable on the `AbortSignal`'s
`reason` property.
Triggers the abort signal, causing the `abortController.signal` to emit
the `'abort'` event.
### `abortController.signal`
<!-- YAML
added:
- v15.0.0
- v14.17.0
-->
* Type: {AbortSignal}
## Class: `AbortSignal`
<!-- YAML
added:
- v15.0.0
- v14.17.0
-->
* Extends: {EventTarget}
The `AbortSignal` is used to notify observers when the
`abortController.abort()` method is called.
### Static method: `AbortSignal.abort([reason])`
<!-- YAML
added:
- v15.12.0
- v14.17.0
changes:
- version:
- v17.2.0
- v16.14.0
pr-url: https://github.com/nodejs/node/pull/40807
description: Added the new optional reason argument.
-->
* `reason` {any}
* Returns: {AbortSignal}
Returns a new already aborted `AbortSignal`.
### Static method: `AbortSignal.timeout(delay)`
<!-- YAML
added:
- v17.3.0
- v16.14.0
-->
* `delay` {number} The number of milliseconds to wait before triggering
the AbortSignal.
Returns a new `AbortSignal` which will be aborted in `delay` milliseconds.
### Static method: `AbortSignal.any(signals)`
<!-- YAML
added:
- v20.3.0
- v18.17.0
-->
* `signals` {AbortSignal\[]} The `AbortSignal`s 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.
### Event: `'abort'`
<!-- YAML
added:
- v15.0.0
- v14.17.0
-->
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'`:
```js
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.
### `abortSignal.aborted`
<!-- YAML
added:
- v15.0.0
- v14.17.0
-->
* Type: {boolean}
True after the `AbortController` has been aborted.
### `abortSignal.onabort`
<!-- YAML
added:
- v15.0.0
- v14.17.0
-->
* Type: {Function}
An optional callback function that may be set by user code to be notified
when the `abortController.abort()` function has been called.
### `abortSignal.reason`
<!-- YAML
added:
- v17.2.0
- v16.14.0
-->
* Type: {any}
An optional reason specified when the `AbortSignal` was triggered.
```js
const ac = new AbortController();
ac.abort(new Error('boom!'));
console.log(ac.signal.reason); // Error: boom!
```
### `abortSignal.throwIfAborted()`
<!-- YAML
added:
- v17.3.0
- v16.17.0
-->
If `abortSignal.aborted` is `true`, throws `abortSignal.reason`.
## `atob(data)`
<!-- YAML
added: v16.0.0
-->
> Stability: 3 - Legacy. Use `Buffer.from(data, 'base64')` instead.
Global alias for [`buffer.atob()`][].
An automated migration is available ([source](https://github.com/nodejs/userland-migrations/tree/main/recipes/buffer-atob-btoa)):
```bash
npx codemod@latest @nodejs/buffer-atob-btoa
```
## Class: `Blob`
<!-- YAML
added: v18.0.0
-->
See {Blob}.
## Class: `BroadcastChannel`
<!-- YAML
added: v18.0.0
-->
See {BroadcastChannel}.
## `btoa(data)`
<!-- YAML
added: v16.0.0
-->
> Stability: 3 - Legacy. Use `buf.toString('base64')` instead.
Global alias for [`buffer.btoa()`][].
An automated migration is available ([source](https://github.com/nodejs/userland-migrations/tree/main/recipes/buffer-atob-btoa)):
```bash
npx codemod@latest @nodejs/buffer-atob-btoa
```
## Class: `Buffer`
<!-- YAML
added: v0.1.103
-->
* Type: {Function}
Used to handle binary data. See the [buffer section][].
## Class: `ByteLengthQueuingStrategy`
<!-- YAML
added: v18.0.0
changes:
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`ByteLengthQueuingStrategy`][].
## `clearImmediate(immediateObject)`
<!-- YAML
added: v0.9.1
-->
[`clearImmediate`][] is described in the [timers][] section.
## `clearInterval(intervalObject)`
<!-- YAML
added: v0.0.1
-->
[`clearInterval`][] is described in the [timers][] section.
## `clearTimeout(timeoutObject)`
<!-- YAML
added: v0.0.1
-->
[`clearTimeout`][] is described in the [timers][] section.
## Class: `CloseEvent`
<!-- YAML
added: v23.0.0
-->
A browser-compatible implementation of {CloseEvent}. Disable this API
with the [`--no-experimental-websocket`][] CLI flag.
## Class: `CompressionStream`
<!-- YAML
added: v18.0.0
changes:
- version:
- v24.7.0
- v22.20.0
pr-url: https://github.com/nodejs/node/pull/59464
description: format now accepts `brotli` value.
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`CompressionStream`][].
## `console`
<!-- YAML
added: v0.1.100
-->
* Type: {Object}
Used to print to stdout and stderr. See the [`console`][] section.
## Class: `CountQueuingStrategy`
<!-- YAML
added: v18.0.0
changes:
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`CountQueuingStrategy`][].
## Class: `Crypto`
<!-- YAML
added:
- v17.6.0
- v16.15.0
changes:
- version: v23.0.0
pr-url: https://github.com/nodejs/node/pull/52564
description: No longer experimental.
- version: v19.0.0
pr-url: https://github.com/nodejs/node/pull/42083
description: No longer behind `--experimental-global-webcrypto` CLI flag.
-->
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`
<!-- YAML
added:
- v17.6.0
- v16.15.0
changes:
- version: v23.0.0
pr-url: https://github.com/nodejs/node/pull/52564
description: No longer experimental.
- version: v19.0.0
pr-url: https://github.com/nodejs/node/pull/42083
description: No longer behind `--experimental-global-webcrypto` CLI flag.
-->
A browser-compatible implementation of the [Web Crypto API][].
## Class: `CryptoKey`
<!-- YAML
added:
- v17.6.0
- v16.15.0
changes:
- version: v23.0.0
pr-url: https://github.com/nodejs/node/pull/52564
description: No longer experimental.
- version: v19.0.0
pr-url: https://github.com/nodejs/node/pull/42083
description: No longer behind `--experimental-global-webcrypto` CLI flag.
-->
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`
<!-- YAML
added:
- v18.7.0
- v16.17.0
changes:
- version: v23.0.0
pr-url: https://github.com/nodejs/node/pull/52723
description: No longer experimental.
- version:
- v22.1.0
- v20.13.0
pr-url: https://github.com/nodejs/node/pull/52618
description: CustomEvent is now stable.
- version: v19.0.0
pr-url: https://github.com/nodejs/node/pull/44860
description: No longer behind `--experimental-global-customevent` CLI flag.
-->
A browser-compatible implementation of {CustomEvent}.
## Class: `DecompressionStream`
<!-- YAML
added: v18.0.0
changes:
- version:
- v24.7.0
- v22.20.0
pr-url: https://github.com/nodejs/node/pull/59464
description: format now accepts `brotli` value.
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`DecompressionStream`][].
## Class: `DOMException`
<!-- YAML
added: v17.0.0
-->
The WHATWG {DOMException} class.
## `ErrorEvent`
<!-- YAML
added: v25.0.0
-->
A browser-compatible implementation of {ErrorEvent}.
## Class: `Event`
<!-- YAML
added: v15.0.0
changes:
- version: v15.4.0
pr-url: https://github.com/nodejs/node/pull/35949
description: No longer experimental.
-->
A browser-compatible implementation of the `Event` class. See
[`EventTarget` and `Event` API][] for more details.
## Class: `EventSource`
<!-- YAML
added:
- v22.3.0
- v20.18.0
-->
> Stability: 1 - Experimental. Enable this API with the [`--experimental-eventsource`][]
> CLI flag.
A browser-compatible implementation of {EventSource}.
## Class: `EventTarget`
<!-- YAML
added: v15.0.0
changes:
- version: v15.4.0
pr-url: https://github.com/nodejs/node/pull/35949
description: No longer experimental.
-->
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`
<!-- YAML
added:
- v17.5.0
- v16.15.0
changes:
- version:
- v21.0.0
pr-url: https://github.com/nodejs/node/pull/45684
description: No longer experimental.
- version: v18.0.0
pr-url: https://github.com/nodejs/node/pull/41811
description: No longer behind `--experimental-fetch` CLI flag.
-->
A browser-compatible implementation of the [`fetch()`][] function.
```mjs
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](https://undici.nodejs.org), 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.
### Custom dispatcher
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](https://undici.nodejs.org/#/docs/api/Dispatcher.md).
```js
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.
```mjs
import { setGlobalDispatcher } from 'undici';
setGlobalDispatcher(new MyAgent());
```
### Related classes
The following globals are available to use with `fetch`:
* [`FormData`][]
* [`Headers`][]
* [`Request`][]
* [`Response`][]
## Class: `File`
<!-- YAML
added: v20.0.0
-->
See {File}.
## Class: `FormData`
<!-- YAML
added:
- v17.6.0
- v16.15.0
changes:
- version:
- v21.0.0
pr-url: https://github.com/nodejs/node/pull/45684
description: No longer experimental.
- version: v18.0.0
pr-url: https://github.com/nodejs/node/pull/41811
description: No longer behind `--experimental-fetch` CLI flag.
-->
A browser-compatible implementation of {FormData}.
## `global`
<!-- YAML
added: v0.1.27
-->
> Stability: 3 - Legacy. Use [`globalThis`][] instead.
* 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`
<!-- YAML
added:
- v17.5.0
- v16.15.0
changes:
- version:
- v21.0.0
pr-url: https://github.com/nodejs/node/pull/45684
description: No longer experimental.
- version: v18.0.0
pr-url: https://github.com/nodejs/node/pull/41811
description: No longer behind `--experimental-fetch` CLI flag.
-->
A browser-compatible implementation of {Headers}.
## `localStorage`
<!-- YAML
added: v22.4.0
changes:
- version: v26.0.0
pr-url: https://github.com/nodejs/node/pull/60351
description: Accessing the `localStorage` global without providing
`--localstorage-file` now throws a `DOMException`, for
compliance with the Web Storage specification.
- version: v25.0.0
pr-url: https://github.com/nodejs/node/pull/57666
description: When webstorage is enabled and `--localstorage-file` is not
provided, accessing the `localStorage` global now returns an
empty object.
- version: v25.0.0
pr-url: https://github.com/nodejs/node/pull/57666
description: This API is no longer behind `--experimental-webstorage` runtime flag.
-->
> Stability: 1.2 - Release candidate. Disable this API with [`--no-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.
## Class: `MessageChannel`
<!-- YAML
added: v15.0.0
-->
The `MessageChannel` class. See [`MessageChannel`][] for more details.
## Class: `MessageEvent`
<!-- YAML
added: v15.0.0
-->
A browser-compatible implementation of {MessageEvent}.
## Class: `MessagePort`
<!-- YAML
added: v15.0.0
-->
The `MessagePort` class. See [`MessagePort`][] for more details.
## `module`
This variable may appear to be global but is not. See [`module`][].
## Class: `Navigator`
<!-- YAML
added: v21.0.0
-->
> Stability: 1.1 - Active development. Disable this API with the
> [`--no-experimental-global-navigator`][] CLI flag.
A partial implementation of the [Navigator API][].
## `navigator`
<!-- YAML
added: v21.0.0
-->
> Stability: 1.1 - Active development. Disable this API with the
> [`--no-experimental-global-navigator`][] CLI flag.
A partial implementation of [`window.navigator`][].
### `navigator.hardwareConcurrency`
<!-- YAML
added: v21.0.0
-->
* Type: {number}
The `navigator.hardwareConcurrency` read-only property returns the number of
logical processors available to the current Node.js instance.
```js
console.log(`This process is running on ${navigator.hardwareConcurrency} logical processors`);
```
### `navigator.language`
<!-- YAML
added: v21.2.0
-->
* Type: {string}
The `navigator.language` read-only property returns a string representing the
preferred language of the Node.js instance. The language will be determined by
the ICU library used by Node.js at runtime based on the
default language of the operating system.
The value is representing the language version as defined in [RFC 5646][].
The fallback value on builds without ICU is `'en-US'`.
```js
console.log(`The preferred language of the Node.js instance has the tag '${navigator.language}'`);
```
### `navigator.languages`
<!-- YAML
added: v21.2.0
-->
* Type: {string\[]}
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']`.
```js
console.log(`The preferred languages are '${navigator.languages}'`);
```
### `navigator.locks`
<!-- YAML
added: v24.5.0
-->
> 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.
```mjs
// 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}`);
});
```
```cjs
// 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.
### `navigator.platform`
<!-- YAML
added: v21.2.0
-->
* Type: {string}
The `navigator.platform` read-only property returns a string identifying the
platform on which the Node.js instance is running.
```js
console.log(`This process is running on ${navigator.platform}`);
```
### `navigator.userAgent`
<!-- YAML
added: v21.1.0
-->
* Type: {string}
The `navigator.userAgent` read-only property returns user agent
consisting of the runtime name and major version number.
```js
console.log(`The user-agent is ${navigator.userAgent}`); // Prints "Node.js/21"
```
## `performance`
<!-- YAML
added: v16.0.0
-->
The [`perf_hooks.performance`][] object.
## Class: `PerformanceEntry`
<!-- YAML
added: v19.0.0
-->
The `PerformanceEntry` class. See [`PerformanceEntry`][] for more details.
## Class: `PerformanceMark`
<!-- YAML
added: v19.0.0
-->
The `PerformanceMark` class. See [`PerformanceMark`][] for more details.
## Class: `PerformanceMeasure`
<!-- YAML
added: v19.0.0
-->
The `PerformanceMeasure` class. See [`PerformanceMeasure`][] for more details.
## Class: `PerformanceObserver`
<!-- YAML
added: v19.0.0
-->
The `PerformanceObserver` class. See [`PerformanceObserver`][] for more details.
## Class: `PerformanceObserverEntryList`
<!-- YAML
added: v19.0.0
-->
The `PerformanceObserverEntryList` class. See
[`PerformanceObserverEntryList`][] for more details.
## Class: `PerformanceResourceTiming`
<!-- YAML
added: v19.0.0
-->
The `PerformanceResourceTiming` class. See [`PerformanceResourceTiming`][] for
more details.
## `process`
<!-- YAML
added: v0.1.7
-->
* Type: {Object}
The process object. See the [`process` object][] section.
## `queueMicrotask(callback)`
<!-- YAML
added: v11.0.0
-->
* `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.
```js
// 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);
};
```
## Class: `QuotaExceededError`
<!-- YAML
added: v26.0.0
-->
The WHATWG {QuotaExceededError} class. Extends {DOMException}.
## Class: `ReadableByteStreamController`
<!-- YAML
added: v18.0.0
changes:
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`ReadableByteStreamController`][].
## Class: `ReadableStream`
<!-- YAML
added: v18.0.0
changes:
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`ReadableStream`][].
## Class: `ReadableStreamBYOBReader`
<!-- YAML
added: v18.0.0
changes:
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`ReadableStreamBYOBReader`][].
## Class: `ReadableStreamBYOBRequest`
<!-- YAML
added: v18.0.0
changes:
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`ReadableStreamBYOBRequest`][].
## Class: `ReadableStreamDefaultController`
<!-- YAML
added: v18.0.0
changes:
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`ReadableStreamDefaultController`][].
## Class: `ReadableStreamDefaultReader`
<!-- YAML
added: v18.0.0
changes:
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`ReadableStreamDefaultReader`][].
## Class: `Request`
<!-- YAML
added:
- v17.5.0
- v16.15.0
changes:
- version:
- v21.0.0
pr-url: https://github.com/nodejs/node/pull/45684
description: No longer experimental.
- version: v18.0.0
pr-url: https://github.com/nodejs/node/pull/41811
description: No longer behind `--experimental-fetch` CLI flag.
-->
A browser-compatible implementation of {Request}.
## `require()`
This variable may appear to be global but is not. See [`require()`][].
## Class: `Response`
<!-- YAML
added:
- v17.5.0
- v16.15.0
changes:
- version:
- v21.0.0
pr-url: https://github.com/nodejs/node/pull/45684
description: No longer experimental.
- version: v18.0.0
pr-url: https://github.com/nodejs/node/pull/41811
description: No longer behind `--experimental-fetch` CLI flag.
-->
A browser-compatible implementation of {Response}.
## `sessionStorage`
<!-- YAML
added: v22.4.0
changes:
- version: v25.0.0
pr-url: https://github.com/nodejs/node/pull/57666
description: This API is no longer behind `--experimental-webstorage` runtime flag.
-->
> Stability: 1.2 - Release candidate. Disable this API with [`--no-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.
## `setImmediate(callback[, ...args])`
<!-- YAML
added: v0.9.1
-->
[`setImmediate`][] is described in the [timers][] section.
## `setInterval(callback, delay[, ...args])`
<!-- YAML
added: v0.0.1
-->
[`setInterval`][] is described in the [timers][] section.
## `setTimeout(callback, delay[, ...args])`
<!-- YAML
added: v0.0.1
-->
[`setTimeout`][] is described in the [timers][] section.
## Class: `Storage`
<!-- YAML
added: v22.4.0
-->
> Stability: 1.2 - Release candidate. Disable this API with [`--no-experimental-webstorage`][].
A browser-compatible implementation of {Storage}.
## `structuredClone(value[, options])`
<!-- YAML
added: v17.0.0
-->
The WHATWG [`structuredClone`][] method.
## Class: `SubtleCrypto`
<!-- YAML
added:
- v17.6.0
- v16.15.0
changes:
- version: v19.0.0
pr-url: https://github.com/nodejs/node/pull/42083
description: No longer behind `--experimental-global-webcrypto` CLI flag.
-->
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: `TextDecoder`
<!-- YAML
added: v11.0.0
-->
The WHATWG `TextDecoder` class. See the [`TextDecoder`][] section.
## Class: `TextDecoderStream`
<!-- YAML
added: v18.0.0
changes:
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`TextDecoderStream`][].
## Class: `TextEncoder`
<!-- YAML
added: v11.0.0
-->
The WHATWG `TextEncoder` class. See the [`TextEncoder`][] section.
## Class: `TextEncoderStream`
<!-- YAML
added: v18.0.0
changes:
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`TextEncoderStream`][].
## Class: `TransformStream`
<!-- YAML
added: v18.0.0
changes:
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`TransformStream`][].
## Class: `TransformStreamDefaultController`
<!-- YAML
added: v18.0.0
changes:
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`TransformStreamDefaultController`][].
## Class: `URL`
<!-- YAML
added: v10.0.0
-->
The WHATWG `URL` class. See the [`URL`][] section.
## Class: `URLPattern`
<!-- YAML
added: v24.0.0
-->
> Stability: 1 - Experimental
The WHATWG `URLPattern` class. See the [`URLPattern`][] section.
## Class: `URLSearchParams`
<!-- YAML
added: v10.0.0
-->
The WHATWG `URLSearchParams` class. See the [`URLSearchParams`][] section.
## Class: `WebAssembly`
<!-- YAML
added: v8.0.0
-->
* Type: {Object}
The object that acts as the namespace for all W3C
[WebAssembly][webassembly-org] related functionality. See the
[Mozilla Developer Network][webassembly-mdn] for usage and compatibility.
## Class: `WebSocket`
<!-- YAML
added:
- v21.0.0
- v20.10.0
changes:
- version: v22.4.0
pr-url: https://github.com/nodejs/node/pull/53352
description: No longer experimental.
- version: v22.0.0
pr-url: https://github.com/nodejs/node/pull/51594
description: No longer behind `--experimental-websocket` CLI flag.
-->
A browser-compatible implementation of {WebSocket}. Disable this API
with the [`--no-experimental-websocket`][] CLI flag.
## Class: `WritableStream`
<!-- YAML
added: v18.0.0
changes:
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`WritableStream`][].
## Class: `WritableStreamDefaultController`
<!-- YAML
added: v18.0.0
changes:
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`WritableStreamDefaultController`][].
## Class: `WritableStreamDefaultWriter`
<!-- YAML
added: v18.0.0
changes:
- version:
- v23.11.0
- v22.15.0
pr-url: https://github.com/nodejs/node/pull/57510
description: Marking the API stable.
-->
A browser-compatible implementation of [`WritableStreamDefaultWriter`][].
[CommonJS module]: modules.md
[CommonJS modules]: modules.md
[ECMAScript module]: esm.md
[Navigator API]: https://html.spec.whatwg.org/multipage/system-state.html#the-navigator-object
[RFC 5646]: https://www.rfc-editor.org/rfc/rfc5646.txt
[Web Crypto API]: webcrypto.md
[`--experimental-eventsource`]: cli.md#--experimental-eventsource
[`--localstorage-file`]: cli.md#--localstorage-filefile
[`--no-experimental-global-navigator`]: cli.md#--no-experimental-global-navigator
[`--no-experimental-websocket`]: cli.md#--no-experimental-websocket
[`--no-experimental-webstorage`]: cli.md#--no-experimental-webstorage
[`ByteLengthQueuingStrategy`]: webstreams.md#class-bytelengthqueuingstrategy
[`CompressionStream`]: webstreams.md#class-compressionstream
[`CountQueuingStrategy`]: webstreams.md#class-countqueuingstrategy
[`DecompressionStream`]: webstreams.md#class-decompressionstream
[`EventTarget` and `Event` API]: events.md#eventtarget-and-event-api
[`FormData`]: #class-formdata
[`Headers`]: #class-headers
[`LockManager`]: worker_threads.md#class-lockmanager
[`MessageChannel`]: worker_threads.md#class-messagechannel
[`MessagePort`]: worker_threads.md#class-messageport
[`PerformanceEntry`]: perf_hooks.md#class-performanceentry
[`PerformanceMark`]: perf_hooks.md#class-performancemark
[`PerformanceMeasure`]: perf_hooks.md#class-performancemeasure
[`PerformanceObserverEntryList`]: perf_hooks.md#class-performanceobserverentrylist
[`PerformanceObserver`]: perf_hooks.md#class-performanceobserver
[`PerformanceResourceTiming`]: perf_hooks.md#class-performanceresourcetiming
[`ReadableByteStreamController`]: webstreams.md#class-readablebytestreamcontroller
[`ReadableStreamBYOBReader`]: webstreams.md#class-readablestreambyobreader
[`ReadableStreamBYOBRequest`]: webstreams.md#class-readablestreambyobrequest
[`ReadableStreamDefaultController`]: webstreams.md#class-readablestreamdefaultcontroller
[`ReadableStreamDefaultReader`]: webstreams.md#class-readablestreamdefaultreader
[`ReadableStream`]: webstreams.md#class-readablestream
[`Request`]: #class-request
[`Response`]: #class-response
[`TextDecoderStream`]: webstreams.md#class-textdecoderstream
[`TextDecoder`]: util.md#class-utiltextdecoder
[`TextEncoderStream`]: webstreams.md#class-textencoderstream
[`TextEncoder`]: util.md#class-utiltextencoder
[`TransformStreamDefaultController`]: webstreams.md#class-transformstreamdefaultcontroller
[`TransformStream`]: webstreams.md#class-transformstream
[`URLPattern`]: url.md#class-urlpattern
[`URLSearchParams`]: url.md#class-urlsearchparams
[`URL`]: url.md#class-url
[`WritableStreamDefaultController`]: webstreams.md#class-writablestreamdefaultcontroller
[`WritableStreamDefaultWriter`]: webstreams.md#class-writablestreamdefaultwriter
[`WritableStream`]: webstreams.md#class-writablestream
[`__dirname`]: modules.md#__dirname
[`__filename`]: modules.md#__filename
[`abortSignal.reason`]: #abortsignalreason
[`buffer.atob()`]: buffer.md#bufferatobdata
[`buffer.btoa()`]: buffer.md#bufferbtoadata
[`clearImmediate`]: timers.md#clearimmediateimmediate
[`clearInterval`]: timers.md#clearintervaltimeout
[`clearTimeout`]: timers.md#cleartimeouttimeout
[`console`]: console.md
[`exports`]: modules.md#exports
[`fetch()`]: https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch
[`globalThis`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/globalThis
[`localStorage`]: https://developer.mozilla.org/en-US/docs/Web/API/Window/localStorage
[`module`]: modules.md#module
[`perf_hooks.performance`]: perf_hooks.md#perf_hooksperformance
[`process.nextTick()`]: process.md#processnexttickcallback-args
[`process` object]: process.md#process
[`require()`]: modules.md#requireid
[`sessionStorage`]: https://developer.mozilla.org/en-US/docs/Web/API/Window/sessionStorage
[`setImmediate`]: timers.md#setimmediatecallback-args
[`setInterval`]: timers.md#setintervalcallback-delay-args
[`setTimeout`]: timers.md#settimeoutcallback-delay-args
[`structuredClone`]: https://developer.mozilla.org/en-US/docs/Web/API/Window/structuredClone
[`window.navigator`]: https://developer.mozilla.org/en-US/docs/Web/API/Window/navigator
[`worker_threads.locks`]: worker_threads.md#worker_threadslocks
[browser `LockManager`]: https://developer.mozilla.org/en-US/docs/Web/API/LockManager
[buffer section]: buffer.md
[built-in objects]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects
[timers]: timers.md
[webassembly-mdn]: https://developer.mozilla.org/en-US/docs/WebAssembly
[webassembly-org]: https://webassembly.org