If you use Emacs, you can use Flycheck to check your .js files on the fly using Flow.
Here is the checker definition I use:
I prefer to use Flow after gjslint, so I define the following, too:
Hi! I'm Lorenzo Bolla, Senior Software Architect in London, UK.
When I'm not programming in Python, Rust, Go or Haskell, I am playing either basketball, piano or chess.