AbortSignal

The AbortSignal interface represents a signal object that allows you to communicate with a DOM request (such as a Fetch) and abort it if required via an AbortController object.

Properties

The AbortSignal interface also inherits properties from its parent interface, EventTarget.

AbortSignal.aborted Read only
A Boolean that indicates whether the request(s) the signal is communicating with is/are aborted (true) or not (false).

Events

Listen to this event using addEventListener() or by assigning an event listener to the oneventname property of this interface.

abort
Invoked when the DOM request(s) the signal is communicating with is/are aborted.
Also available via the onabort property.

Methods

The AbortSignal interface inherits methods from its parent interface, EventTarget.

Static methods

AbortSignal.abort()
Returns an AbortSignal instance that is already set as aborted.

Examples

In the following snippet, we aim to download a video using the Fetch API.

We first create a controller using the AbortController() constructor, then grab a reference to its associated AbortSignal object using the AbortController.signal property.

When the fetch request is initiated, we pass in the AbortSignal as an option inside the request's options object (see {signal}, below). This associates the signal and controller with the fetch request and allows us to abort it by calling AbortController.abort(), as seen below in the second event listener.

var controller = new AbortController();
var signal = controller.signal;

var downloadBtn = document.querySelector('.download');
var abortBtn = document.querySelector('.abort');

downloadBtn.addEventListener('click', fetchVideo);

abortBtn.addEventListener('click', function() {
  controller.abort();
  console.log('Download aborted');
});

function fetchVideo() {
  ...
  fetch(url, {signal}).then(function(response) {
    ...
  }).catch(function(e) {
    reports.textContent = 'Download error: ' + e.message;
  })
}

Note

When abort() is called, the fetch() promise rejects with an AbortError.

Warning

Current versions of Firefox rejects the promise with a DOMException

You can find a full working example on GitHub — see abort-api (see it running live also).

Specifications

Specification Status Comment
DOM
The definition of 'AbortSignal' in that specification.
Living Standard Initial definition

Browser compatibility

BCD tables only load in the browser

See also