Completion values in JavaScript
Written by Stefan Judis
- Published at
- Updated at
- Reading time
- 1min
This post is part of my Today I learned series in which I share all my web development learnings.
Paul Irish tweeted a while back a code snippet that puzzled him (and me).
> "omg"; var x = 4;
// "omg"
> eval( `"omg"; var x = 4;` );
// "omg"
We both expected that the "return value" of this lines will be undefined. It turns out what we see after evaluating these lines in a JavaScript console are not return values but rather a statement completion values. If you want to dig deeper in this topic Matt Zeunert enlightened me with his article.
If you enjoyed this article...
Join 6.1k readers and learn something new every week with Web Weekly.
Reply to this post and share your thoughts via good old email.
Frontend nerd with over ten years of experience, freelance dev, "Today I Learned" blogger, conference speaker, and Open Source maintainer.