JavaScript waitForTime

By  on  

I write a lot of tests for new features within Firefox DevTools. We have hundreds of "mochitests" which open the browser and perform synthetic actions like clicking, typing, and other user actions. I've previously written about waitForever which essentially halts following actions without locking the browser. Another utility I enjoy is waitForTime, an async JavaScript function that I can await to give breathing time between two tasks.

Whenever I want to wait a given amount of time between tasks, I employ this function:

function waitForTime(ms) {
  return new Promise(r => setTimeout(r, ms));
}

/* Usage */
await waitForTime(200);
// ...do other thing...
await waitForTime(200);
// ...do next thing ...

It's important to point out that most waitForTime calls don't appear in the final test, since arbitrary timeouts lead to intermittent test failures, but they are helpful in knowing where I need to add polling for some other condition!

Recent Features

  • By
    CSS @supports

    Feature detection via JavaScript is a client side best practice and for all the right reasons, but unfortunately that same functionality hasn't been available within CSS.  What we end up doing is repeating the same properties multiple times with each browser prefix.  Yuck.  Another thing we...

  • By
    Create Namespaced Classes with MooTools

    MooTools has always gotten a bit of grief for not inherently using and standardizing namespaced-based JavaScript classes like the Dojo Toolkit does.  Many developers create their classes as globals which is generally frowned up.  I mostly disagree with that stance, but each to their own.  In any event...

Incredible Demos

  • By
    dat.gui:  Exceptional JavaScript Interface Controller

    We all love trusted JavaScript frameworks like MooTools, jQuery, and Dojo, but there's a big push toward using focused micro-frameworks for smaller purposes. Of course, there are positives and negatives to using them.  Positives include smaller JS footprint (especially good for mobile) and less cruft, negatives...

  • By
    CSS Vertical Centering

    Front-end developing is beautiful, and it's getting prettier by the day. Nowadays we got so many concepts, methodologies, good practices and whatnot to make our work stand out from the rest. Javascript (along with its countless third party libraries) and CSS have grown so big, helping...

Discussion

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