Yes, the source-map support in browsers really needs to improve. NodeJS is another matter though as, in my experience, it maps seamlessly.<p>I think Coffeescript, TypeScript and Babel (ES6 and JSX) are completely different beasts to Elm though. I can look at the compiled output of these languages and debug that, I don&#x27;t really need source maps (though they would be nice).<p>I guess the idea for Elm is, you won&#x27;t need to debug as you won&#x27;t get runtime errors.