Ship the source code along the transpiled code

Shipping the source code along the transpiled code makes it easier for end-user to browse the source-code of the app, and understanding the underlaying logic. This code is never shipped to the client and is only for dev UX: the only downside of this approach is a slightly larger download for the dev.

Amongst other things, see this: https://www.typescriptlang.org/tsconfig/#sourceMap