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

  • By
    Responsive Images: The Ultimate Guide

    Chances are that any Web designers using our Ghostlab browser testing app, which allows seamless testing across all devices simultaneously, will have worked with responsive design in some shape or form. And as today's websites and devices become ever more varied, a plethora of responsive images...

  • By
    Animated 3D Flipping Menu with CSS

    CSS animations aren't just for basic fades or sliding elements anymore -- CSS animations are capable of much more.  I've showed you how you can create an exploding logo (applied with JavaScript, but all animation is CSS), an animated Photo Stack, a sweet...

Incredible Demos

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!