I haven't managed to break into the JS-adjacent ecosystem, but tooling around Typescript is definitely a major part of the problem:

• following a basic tutorial somehow ended up spending multiple seconds just to transpile and run "Hello, World!".
• there are at least 3 different ways of specifying the files and settings you want to use, and some of them will cause others to be ignored entirely, even though it looks like they should be used.
• embracing duck typing means many common type errors simply cannot be caught. Also that means dynamic type checks are impossible, even though JS itself supports them (admittedly with oddities, e.g. with string vs String).
• there are at least 3 incompatible ways to define and use a "module", and it's not clear what's actually useful or intended to be used, or what the outputs are supposed to be for different environments.

At this point I'm seriously considering writing my own sanelanguage-to-JS transpiler or using some other one (maybe Haxe? but I'm not sure its object model allows full performance tweaking), because I've written literally dozens of other languages without this kind of pain.

WASM has its own problems (we shouldn't be quick to call asm.js obsolete ... also, C's object model is not what people think it is) but that's another story.

At this point, I'd be happy with some basic code reuse. Have a "generalized fibonacci" module taking 3 inputs, and call it 3 ways: from a web browser on the client side, as a web browser request to server (which is running nodejs), or as a nodejs command-line program. Transpiling one of the callers should not force the others to be transpiled, but if multiple of the callers need to be transpiled at once, it should not typecheck the library internals multiple times. I should also be able to choose whether to produce a "dynamic" library (which can be recompiled later without recompiling the dependencies) or a "static" one (only output a single merged file), and whether to minify.

I'm not sure the TS ecosystem is competent enough to deal with this.