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
    CSS Transforms

    CSS has become more and more powerful over the past few years and CSS transforms are a prime example. CSS transforms allow for sophisticated, powerful transformations of HTML elements.  One or more transformations can be applied to a given element and transforms can even be animated...

  • By
    Duplicate DeSandro’s CSS Effect

    I recently stumbled upon David DeSandro's website when I saw a tweet stating that someone had stolen/hotlinked his website design and code, and he decided to do the only logical thing to retaliate:  use some simple JavaScript goodness to inject unicorns into their page.

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!