Enzyme : Enzyme is a JavaScript Testing utility for React that makes it easier to assert, manipulate, and traverse your React Components' output.
Online javascript beautifier : Beautify, unpack or deobfuscate JavaScript and HTML, make JSON/JSONP readable, etc.
yepnope.js : A Conditional Loader For Your Polyfills!
jscs is a code style checker. jscs can check cases, which are not implemented in jshint, but it does not duplicate jshint functionality, so you should use jscs and jshint together.