Flow | A static type checker for JavaScriptCode Faster.Tired of having to run your code to find bugs? Flow identifies problems as you code. Stop wasting your time guessing and checking. Code Smarter.It's hard to build smart tools for dynamic languages like JavaScript. Flow understands your code and makes its knowledge available, enabling other smart tools to be built on top of Flow. Code Confidently.Making major changes to large codebases
Jest
