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Cancel async operations with AbortController

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This blog post is part of the series What’s new in Node.js core?

If you want to cancel an async operation in Node.js, such as an HTTP request, you can now use the built in AbortController and AbortSignal classes. They were originally introduced in the Web Platform APIs, which are implemented by web browsers.

Example with node-fetch

Here’s an example of using an AbortSignal with the node-fetch library:

import fetch from "node-fetch";
import { setTimeout } from "node:timers/promises";

const cancelTimeout = new AbortController();
const cancelRequest = new AbortController();

async function timeout(milliseconds) {
	try {
		await setTimeout(milliseconds, undefined, { signal: cancelTimeout.signal });
		cancelRequest.abort();
	} catch (error) {
		// Ignore rejections
	}
}

async function makeRequest() {
	try {
		const response = await fetch("http://localhost:3000/", {
			signal: cancelRequest.signal,
		});
		const responseData = await response.json();

		return responseData;
	} catch (error) {
		if (error.name === "AbortError") {
			console.error("Request was aborted");
		} else {
			console.error(error);
		}
	} finally {
		cancelTimeout.abort();
	}
}

const result = await Promise.race([timeout(2000), makeRequest()]);

console.log({ result });

Support

Support in Node.js versions:

  • Added (Experimental): v15.0.0
  • Graduated (Stable): v15.4.0
  • Backported (Experimental): v14.17.0

Some methods in core Node.js modules now accept AbortSignal instances:

  • http / https
  • fs
  • timers
  • events
  • child_process
  • dgram

See the v14.17.0 release notes for details.

Libraries like node-fetch also accept an AbortSignal instance as an option.

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