I write pure TS code, and I never use sourcemaps to debug (Chrome Dev Tools has a setting that allows you to disable using sourcemaps). And our code is setup t

I write pure TS code, and I never use sourcemaps to debug (Chrome Dev Tools has a setting that allows you to disable using sourcemaps). And our code is setup to compile to ES2015, I believe. The reason is simple. Typescript's compilation to JS is really straightforward. You can predict the code that will be generated trivially, because the vast majority of the time it does nothing more than stripping away types. Since we compile down to ES2015, there are a few additional trivial transformations to handle unsupported features like "let" correctly, but they are also trivial to understand.