For example: The npm package "is-even" depends on the "is-odd" package. (In case it's not clear, this is a real package, not a made-up example.) In most other languages, these would be bundled together into an Integer Utilties package, if they're not already part of the standard library. In NPM, they are separate packages.
I believe there is, or was, a technical reason for NPM to have very fine-grained imports. Perhaps something about not supporting partial imports? I can't exactly find it. But the point is: NPM having more packages does not translate to a larger and more vibrant ecosystem. In some cases it simply means accomplishing the same thing requires a larger dependency graph.
That's not to say it's inherently a bad thing. But that's at least why it's not inherently a good thing either.
People should not be using these functions at all, in any language, in a standard library or otherwise. To convert the even/oddness of an integer to a boolean in Javascript you can use !!(n % 2), which returns true for odd inputs, and false for even inputs. If you want to be extra explicit you can temporarily store the result of that expression in a meaningfully named variable. If it will just be used in a conditional, then the !! can be skipped.
Depending on a third-party package for this kind of thing is insanity. But the blame lies with programmers who use this package, not with the programming language.
If this is very performance sensitive you can try using the somewhat more obscure (because many people have minimal experience with bitwise operators) `n & 1` instead.
Given an integer input, thare are no "edge cases" to worry about here. If you expect floating point inputs, you need to think carefully about what the correct output should be anyway. A library isn’t going to save you.
(If your "edge case" is that someone might want to know whether a string is even or odd... well, you have other problems.)
If you have a use case where you need to know if you multiplied two large integers and got a result larger than 2^53, then you should do it explicitly before you get to the point of checking if your number is even or odd.
This is the root of all the many issues. There is no standard library. So things that are trivial to write but also dumb to rewrite every time you need them (left-pad a great example) turn into tiny dependencies.