Idle JavaScript Observations

There are lots of blogs that post useful tips and observations about programming in JavaScript and other languages.

This is not one of them.

Sometimes I like to look at the label documentation for JavaScript on MDN and ponder unusual ways I can use it:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/label

The way Svelte makes use of the label syntax is actually kind of interesting. When I did a deep-dive into that framework last year this jumped out.

But a deep-dive into labels and scoping might actually be useful. This post is just to let you know that this is valid JavaScript:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/label

In fact, copying-and-pasting just about any URL is probably valid JavaScript.

Why is this?

• The http(s) protcol gets interpreted as the aforementioned label.
• The // immediately following the label starts a comment.

The lowdown: you can copy and paste just about any website directly into your JavaScript code without modification and it won't break anything.

Is this useful? Not really. Just a funny observation I learned the hard way, when I forgot to copy out the reference to some documentation elsewhere in my code.

→ Filed under: Useless JavaScript.