It wouldn't be the same and that would be a GOOD thing. Chez scheme is probably about as fast as JS JITs and with only a fraction of the time spent creating it

It wouldn't be the same and that would be a GOOD thing. Chez scheme is probably about as fast as JS JITs and with only a fraction of the time spent creating it. If you restrict continuations, you can get even better performance. On the flip side, new JS features like BigInt would have existed from the start (along with generators, rest/spread, typed arrays, let/const, etc). Features like threads that don't exist probably would exist. On the better side, all the terrible things people complain about like hoisting, `with`, type coercion, weird prototypal inheritance, bad Java-based dates, etc simply wouldn't have happened because Scheme already specced out most of the relevant things. HTML would have likely disappeared over time because innerHTML and string parsing would be radically less efficient than just using the macros. We wouldn't have 10 different versions of JS because most of the new stuff either would have been baked into the first version or could be easily accomplished with macros. Major versions would be little things like adding optional type hints or CSS wouldn't exist because you'd create sets of styles with lisp lists then pass them in. It would be a better version of CSS in JS, but done 25 years ago. JSON wouldn't have been discovered because lists do all the things better. Likewise, there wouldn't be a need for the "lost decade" of XML development because those same scheme macros would do that job and transformer macros are far easier and better to write than XSLT.