Ask HN: Why doesn’t a time travel debugger exist yet for JavaScript?

Ask HN: Why doesn’t a time travel debugger exist yet for JavaScript? I know Microsoft had a project going for this that is almost certainly scrapped now because Chakra went the way of the dodo but between Facebook, Google, Microsoft, and Mozilla there is some pretty good backing behind JavaScript projects. It seems like you could make a pretty good integration with a browser that would make this valuable.

Source: news.ycombinator.com