i) Never had a problem with this, although I use very very few libraries, so that might be why. (At this point basically only preact)
ii) Yes, but this can't be used to favor JS instead. If a library is badly documented, you're going to have a hard time whether using TS or JS.
iii) This is true, but it depends on what you are doing. One advice is to avoid defining complex types. Another good measure is to sometimes suppress type checking on a few lines that you know are correct but are near impossible for the compiler to verify.
iv) I use esbuild to compile, and have a tsc -watch window open all the time.
ii) Yes, but this can't be used to favor JS instead. If a library is badly documented, you're going to have a hard time whether using TS or JS.
iii) This is true, but it depends on what you are doing. One advice is to avoid defining complex types. Another good measure is to sometimes suppress type checking on a few lines that you know are correct but are near impossible for the compiler to verify.
iv) I use esbuild to compile, and have a tsc -watch window open all the time.