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

abortController.abort()#

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

abortController.signal#

• Type: <AbortSignal>

Class: AbortSignal#

• Extends: <EventTarget>

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

Event: 'abort'#

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. 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#

• Type: <boolean> True after the AbortController has been aborted.

abortSignal.onabort#

• Type: <Function>

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

Class: Buffer#

• <Function>

Used to handle binary data. See the buffer section.

__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.

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.

console#

• <Object>

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

Event#

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

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.

global#

• <Object> The global namespace object.

In browsers, the top-level scope is the global scope. This means that within the browser var something will define a new global variable. 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.

MessageChannel#

The MessageChannel class. See MessageChannel for more details.

MessageEvent#

The MessageEvent class. See MessageEvent for more details.

MessagePort#

The MessagePort class. See MessagePort for more details.

module#

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

process#

• <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(url);
  if (hit !== undefined) {
    queueMicrotask(() => {
      this.emit('load', hit);
    });
    return;
  }

  const data = await fetchData(key);
  this._cache.set(url, data);
  this.emit('load', data);
};

require()#

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

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.

TextDecoder#

The WHATWG TextDecoder class. See the TextDecoder section.

TextEncoder#

The WHATWG TextEncoder class. See the TextEncoder section.

URL#

The WHATWG URL class. See the URL section.

URLSearchParams#

The WHATWG URLSearchParams class. See the URLSearchParams section.

WebAssembly#

• <Object>

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