Quokka.js - a REPL for your js-fu!
So - you're deep into variables not holding their liquer and pure functions not returning what you'd expect them to! What to dooooo...wait a minute, what is this? What is Quokka?
A rapid prototyping playground - executing your code right in your code editor - period
- and you'll get it right here made by the good folks at Wallaby.js