推荐一个工具 babel-watch，比 nodemon 快好多

[TangMonk]

babel-watch only starts babel in the "master" process where it also starts the file watcher. The transpilation is performed in that process too. On file-watcher events, it spawns a pure node process and passes transpiled code from the parent process together with the source maps. This allows us to avoid loading babel and all its deps every time we restart the JS script/app.

https://github.com/kmagiera/babel-watch