In the browser, Javascript’s role is to add interactivity to the web page, and the API has a good surface area (even if not really pretty). People talk about the lack of standard library, but they can never say what’s missing.
I suppose we could quibble about what exactly “standard library” means, but I’m presuming we’re talking about the web (rather than, say, Node or Bun). And to me it’s fair to use it to refer to all web APIs that are widely available. Things like crypto, ArrayBuffer, TextEncoder, File and the File System Access API, Intl, the Streams API, Window.performance, etc.
Most things in Remeda, ramda, rxjs, the methods in the Ruby stdlib, etc. would all be great to have. I use at least Remeda in every project when I can.
Python and Rust have such a thing, but not e.g. Java, Go, C#. And I can't find any libraries on npm which do this. That seems like a very niche need, not actually the sort of thing whose absence causes people to have lots of npm dependencies.
Math.clamp is a big one (it’s a TC39 proposal). I’d also love to have the stats functions that Python has (geometric mean, median, etc.).
On the more ambitious end: CSV reading/writing and IPv4/IPv6 manipulation.