Using typed JavaScript

JavaScript is a dynamically typed language. This means you can change the type of a variable after its initialization. While this can be very handy for small scripts, it can lead to difficult problems when working on large-scale projects. Debugging such errors, especially in apps with a lot of users, can get really messy.

This is where extensions to JavaScript come into play. There are multiple solutions to extend JavaScript to be a typed language. This not only prevents errors; it also enables better refactoring and code completion as well as pointing out problems directly when writing the code.

This speeds up the development process a lot. I would definitely recommend using typed JavaScript and I want to introduce the two most popular solutions here.

Flow

Created and open sourced by Facebook, Flow is a static type checker that works with normal JavaScript. It was created as a command-line tool that scans your files for type safety and reports errors...