[solardev]

Some things are easy now, but some things still require multiple lines of code: https://youmightnotneed.com/lodash. If you only need one or two, sure, just write your own, but if you're maintaining a big project... why waste time debugging these common utility functions? You'd basically just be reinventing lodash, but with fewer community eyes and tests on it. Whoever inherits that is gonna need to debug all your util functions when something inevitably goes wrong. Like for _.pickBy(), none of these are very readable (https://stackoverflow.com/questions/54743996/converting-loda...), another implements it wrong and leaves out the predicate (https://github.com/you-dont-need/You-Dont-Need-Lodash-Unders...), etc. Why do this to your project and fellow devs when it can easily be a single tree-shaken function imported from a popular, well-maintained lib?

If anything, ECMA should just absorb more lodash functions into the standard lib, like they've gradually done with some of the array functions. But common things like that shouldn't be up to each individual programmer & team to reinvent all the time. It just needlessly expands the maintenance surface and causes subtle bugs across teams & projects.

JS Date is in an even worse place. If you ever need to work across time zones on both the server and the client/browser, native JS date is totally unusable because it "loses" the original time zone string and just coerces everything into (basically) utc milliseconds. The Temporal API is supposed to fix that, but I've been waiting for that for nearly a decade: https://tc39.es/proposal-temporal/docs/. That proposal links to https://maggiepint.com/2017/04/09/fixing-javascript-date-get..., which explains some of the weaknesses of the current JS date system.

[chrysoprace]

I agree with you about timezones and I think a library like date-fns (and date-fns-tz) strike a nice balance by not using a bespoke intermediary object type.

As you say, some of them are built in and those should just be used instead in most cases. The problem is that when you leave the choice of library to use, then the choice isn't always obvious, especially for niche use cases. A library that's well-maintained today may not be so tomorrow when the maintainer falls ill, gets burnt out on work + open source work or simply gets bored of the project.

Deno has the right approach in this regard where they are creating standard libraries to go with their runtime which are expected to be maintained in the long term, but even then I'd still prefer built-in APIs in most cases.