Return a Default Value with Promises Using catch

By  on  

Last week I tweeted all of you looking for your best JavaScript Array and Promise tricks, and as always, it didn't disappoint -- I learned quite a bit!

Today's JavaScript Promise trick is brought to you by Claudio Semeraro: how to use catch to set a default value instead of a try/catch:

// Instead of wrapping this block in a try/catch...
const result = await new Promise(
  (resolve, reject) => reject("Because Stone Cold said so")
)
// ...use catch to set the default value (100)
.catch(() => 100);

As a trick I really like what's this brings; as far as readability and maintenance, if you don't know the trick, you might get confused. What do you think?

Recent Features

Incredible Demos

  • By
    CSS Ellipsis Beginning of String

    I was incredibly happy when CSS text-overflow: ellipsis (married with fixed width and overflow: hidden was introduced to the CSS spec and browsers; the feature allowed us to stop trying to marry JavaScript width calculation with string width calculation and truncation.  CSS ellipsis was also very friendly to...

  • By
    Multiple File Upload Input

    More often than not, I find myself wanting to upload more than one file at a time.  Having to use multiple "file" INPUT elements is annoying, slow, and inefficient.  And if I hate them, I can't imagine how annoyed my users would be.  Luckily Safari, Chrome...

Discussion

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