Completion values in JavaScript
- Published at
- Updated at
- Reading time
- 1min
This post is part of my Today I learned series in which I share all my learnings regarding web development.
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.