Yes. We develop a large Angular app. When the framework itself is written in TypeScript, and by extension, most of the ecosystem code ends up being TypeScript a

Yes. We develop a large Angular app. When the framework itself is written in TypeScript, and by extension, most of the ecosystem code ends up being TypeScript as well, and we have not really faced any major typing issues. On the other hand, when writing server code targeting Node, with lots of dependencies on micro-libs, I've definitely had the experience of struggling with outdated or incorrect type definitions. However, nowadays TypeScript has much better interoperability with untyped JS code. You can generally import an untyped JS module with the minimum of ceremony and have it Just Work (the type will be "any", so you don't get intellisense). I find the best approach is to import types for the big libs you are using, like Express, and leave the micro-libs untyped. That way you get the benefit of types on your own code and your interactions with the framework, but can still leverage other code when you need to without giving yourself a headache.