Chrome extension codebase has both javascript and typescript

Question

Am working on an existing codebase for a chrome extension, was wondering why each javascript file had a typescript duplicate that seemingly does the same thing. Not sure if any of the typescript functions are even being utilized. Is there a specific reason why the previous coder would have done this?

Answer 1

Check the tsconfig file to verify the output directory used by typescrpt compiler. Ideally output directory should be placed outside source files(typscript version)