I had a lot of gotchas with babel too, until I realized one thing, that should be featured prominently in every bug-tracker having anything to do with babel: B

I had a lot of gotchas with babel too, until I realized one thing, that should be featured prominently in every bug-tracker having anything to do with babel: Babel will look for a .babelrc in the current directory of the file being transpiled. If one does not exist, it will travel up the directory tree until it finds either a .babelrc, or a package.json with a "babel": {} hash within. - https://babeljs.io/docs/usage/babelrc/ https://babeljs.io/docs/usage/babelrc/ So if you have stray files lying around, they might break your build.