a common thing i've run into this week: packages which exhaustively try to cover every possible edge case. but it turns out almost no consumer calls it in a way that would hit those cases some are 1/4 of the size when you cut those out. sometimes its ok to just... not support things
I'm a huge fan of the Unix philosophy - make the thing do it's single job correctly.
Agreed if you are writing a new thing. It is much harder for widely deployed projects to do this without a costly migration for maintainers. This is why at work I always push hard not to support things until it is CLEARLY necessary. Much harder to do in the distributed system we have in OSS JS.
Also pre-TypeScript libraries that do a bunch of runtime parameter validation