JavaScript waitForever

By  on  
Writing mochitests for new features in DevTools can be difficult and time-consuming.  There are so many elements interacting in an async manner that I oftentimes find myself using the debugger to debug the debugger!  In the case where it's unclear what interaction isn't working properly, I find myself going to a neat utility function: waitForever.  By using this function, paired with await, I can interact with the page while a given test is running to find the problem!

The JavaScript

waitForever is a super small snippet:
function waitForever() {
  return new Promise(r => {});
}

// Usage:
await waitForever();
The function uses a promise which never resolves, thus no additional statements are triggered while also not locking up the browser.  From there I can click around and explore elements to find what I've messed up in my test. Utility functions like these make web development much easier and more enjoyable.  Add this one to your toolbox!

Recent Features

Incredible Demos

  • By
    Send Email Notifications for Broken Images Using jQuery AJAX

    It's usually best to repair broken image paths as soon as possible because they can damage a website's credibility. And even worse is having a user tell you about it. Using jQuery and PHP, you can have your page automatically notify you of broken...

  • By
    Vertically Centering with Flexbox

    Vertically centering sibling child contents is a task we've long needed on the web but has always seemed way more difficult than it should be.  We initially used tables to accomplish the task, then moved on to CSS and JavaScript tricks because table layout was horribly...

Discussion

  1. Kenji Okamoto

    Thanks for the tip David! I’ll keep that in mind when working on mochi tests. Have you found any other uses for this snippet?

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!