It's got to the point where, for me, TypeScript support is an important feature of a library that influences my decision whether to pick that library over anoth

It's got to the point where, for me, TypeScript support is an important feature of a library that influences my decision whether to pick that library over another. Luckily, most of them these days either ship with their own definitions, or have them available. Bottom line: I never write my own definitions for other projects.