What in practice causes the most pain for mé are the various module formats in combination with TS. Just getting my test runner (Mocha) and Node and the bundler and... to work with TS and the chosen module format is always _not_ fun. Combined with package updates that break the current working solution because they now natively support es modules. I hope these problems will all disappear in the future, but I'm somewhat sceptical. And TS is slow - not C++, Haskell and Rust slow, but still. But I never used TS/Node for anything big (backendy), but just small frontends and VS Code extensions, where the time of getting everything set-up to work takes a relatively larger part of the "actual" work.