Software

fetch with Timeout


A few years back I wrote a blog post about how write a fetch Promise that times out. The function was effective but the code wasn’t great, mostly because AbortController , which allows you to cancel a fetch Promise, did not yet exist. With AbortController and AbortSignal available, let’s create a better JavaScript function for fetching with a timeout:

Much like the original function, we’ll use setTimeout to time to the cancellation but we’ll use the signal with the fetch request:

async function fetchWithTimeout(url, opts = {}, timeout = 5000) {
  // Create the AbortController instance, get AbortSignal
  const abortController = new AbortController();
  const { signal } = abortController;

  // Make the fetch request
  const _fetchPromise = fetch(url, {
    ...opts,
    signal,
  });

  // Start the timer
  const timer = setTimeout(() => abortController.abort(), timeout);

  // Await the fetch with a catch in case it's aborted which signals an error
  try {
    const result = await _fetchPromise;
    clearTimeout(timer);
    return result;
  } catch (e) {
    clearTimeout(timer);
    throw e;
  }
};

// Usage
try {
  const impatientFetch = await fetchWithTimeout('/', {}, 2000);
}
catch(e) {
  console.log("fetch possibly canceled!", e);
}

The JavaScript code above is much cleaner now that we have a proper API to cancel fetch Promise calls. Attaching the signal to the fetch request allows us to use a setTimeout with abort to cancel the request after a given amount of time.

It’s been excellent seeing AbortController, AbortSignal, and fetch evolve to make async requests more controllable without drastically changing the API.

  • I’m an Impostor

    This is the hardest thing I’ve ever had to write, much less admit to myself.  I’ve written resignation letters from jobs I’ve loved, I’ve ended relationships, I’ve failed at a host of tasks, and let myself down in my life.  All of those feelings were very…

  • Write Simple, Elegant and Maintainable Media Queries with Sass


Source link
Show More

admin

Makes Noise is a blog where you can find all the juicy details on a variety of topics including health and fitness, technology, lifestyle, entertainment, love and relationships, beauty and makeup, sports and so much more. The blog is updated regularly to make sure you have all the latest and greatest information on the topics that matter most to you.

Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button