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Global Objects

These objects are available in all modules. Some of these objects aren’t actually in the global scope but in the module scope.

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Global Variables

The following variables may appear to be global but exist only in the scope of CommonJS modules:
  • __dirname
  • __filename
  • exports
  • module
  • require()

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Class: AbortController

Added in: v15.0.0, v14.17.0
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

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abortController.abort([reason])

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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.

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abortController.signal

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signal
AbortSignal
The AbortSignal object associated with this AbortController.

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Class: AbortSignal

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

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Static Methods

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AbortSignal.abort([reason])

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reason
any
Optional reason for aborting.
Returns a new already aborted AbortSignal.

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AbortSignal.timeout(delay)

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delay
number
required
The number of milliseconds to wait before triggering the AbortSignal.
Returns a new AbortSignal which will be aborted in delay milliseconds.

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AbortSignal.any(signals)

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signals
AbortSignal[]
required
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.

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Event: ‘abort’

The ‘abort’ event is emitted when the abortController.abort() method is called. 
const ac = new AbortController();

ac.signal.addEventListener('abort', (event) => {
  console.log(event.type);  // Prints 'abort'
}, { once: true });

ac.abort();

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abortSignal.aborted

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aborted
boolean
True after the AbortController has been aborted.

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abortSignal.reason

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reason
any
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!

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abortSignal.throwIfAborted()

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

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Class: Buffer

Added in: v0.1.103
Used to handle binary data. See the Buffer section.

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console

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

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fetch

Added in: v17.5.0, v16.15.0. No longer experimental in v21.0.0.
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 for Node.js. The following globals are available to use with fetch:
  • FormData
  • Headers
  • Request
  • Response

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global

Stability: 3 - Legacy. Use globalThis instead.
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global
Object
The global namespace object.
In browsers, the top-level scope is the global scope. In Node.js, the top-level scope is not the global scope; var something inside a Node.js module will be local to that module.

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performance

Added in: v16.0.0
The perf_hooks.performance object.

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process

Added in: v0.1.7
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process
Object
The process object. See the Process section.

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queueMicrotask(callback)

Added in: v11.0.0
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callback
Function
required
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. 
queueMicrotask(() => {
  console.log('Microtask executed');
});

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Timer Functions

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setImmediate(callback[, …args])

Added in: v0.9.1
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callback
Function
required
The function to call at the end of this turn of the event loop.
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...args
any
Optional arguments to pass when the callback is called.
See the Timers section.

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setInterval(callback, delay[, …args])

Added in: v0.0.1
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callback
Function
required
The function to call when the timer elapses.
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delay
number
The number of milliseconds to wait before calling the callback. Default: 1.
See the Timers section.

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setTimeout(callback, delay[, …args])

Added in: v0.0.1
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callback
Function
required
The function to call when the timer elapses.
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delay
number
The number of milliseconds to wait before calling the callback. Default: 1.
See the Timers section.

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clearImmediate(immediateObject)

Added in: v0.9.1
Cancels an Immediate object created by setImmediate().

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clearInterval(intervalObject)

Added in: v0.0.1
Cancels a Timeout object created by setInterval().

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clearTimeout(timeoutObject)

Added in: v0.0.1
Cancels a Timeout object created by setTimeout().

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URL

Added in: v10.0.0
The WHATWG URL class.

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URLSearchParams

Added in: v10.0.0
The WHATWG URLSearchParams class.

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WebAssembly

Added in: v8.0.0
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WebAssembly
Object
The object that acts as the namespace for all W3C WebAssembly related functionality.