Obviously some of this is subjective, but the main points of frustration are the terrible standard library, the type system requiring you to use things like ===

Obviously some of this is subjective, but the main points of frustration are the terrible standard library, the type system requiring you to use things like ===, !== to prevent crazy type conversions, the total lack of advanced built-in data structures, and the fact that you pretty much need to use transpilers to use all the language features, things like coffee script to get a sane type system etc. JavaScript lugs around a lot of legacy and it leaks out in bad way. That, and I absolutely detest the whole npm ecosystem and most of the rest of the typical JavaScript toolchain. That said, I appreciate its ubiquity, and it does have some nice things lik very good support for functional, reactive and/or async programming styles. But like I said, I may not be entirely objective as I work almost exclusively in C++ and backend Python these days, so JavaScript is pretty far outside my comfort zone anyway.