Use binding.pry in your JavaScript. Literally just a wrapper for debugger. For those who've been writing a lot of Ruby and can't seem to shake the habit.
npm install binding-pry-js
Import the script in your code (or load via CDN) and call binding.pry. A debugger statement will be triggered and you, a Ruby dev, won't feel as stupid as you otherwise would.
import 'binding-pry-js';
binding.pry
// or...
binding.irb