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AbortController: signal property

The signal read-only property of the AbortController interface returns an AbortSignal object instance, which can be used to communicate with/abort a DOM request as desired.

Value

An AbortSignal object instance.

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 (the {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.

js

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

const url = "video.mp4";
const downloadBtn = document.querySelector(".download");
const abortBtn = document.querySelector(".abort");

downloadBtn.addEventListener("click", fetchVideo);

abortBtn.addEventListener("click", () => {
  controller.abort();
  console.log("Download aborted");
});

function fetchVideo() {
  fetch(url, { signal })
    .then((response) => {
      console.log("Download complete", response);
    })
    .catch((err) => {
      console.error(`Download error: ${err.message}`);
    });
}

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

You can find a full working example on GitHub; you can also see it running live.

Specifications

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
signal 66 16 57 No 53 12.1
11.1Even though window.AbortController is defined, it doesn't really abort fetch requests. See bug 174980.
66 66 57 47 12.2
11.3Even though window.AbortController is defined, it doesn't really abort fetch requests. See bug 174980.
9.0

See also

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https://developer.mozilla.org/en-US/docs/Web/API/AbortController/signal