I'm not saying this is impossible but I think you'd have to work rather carefully to not have to parse the code twice and effectively run two type checkers in p

I'm not saying this is impossible but I think you'd have to work rather carefully to not have to parse the code twice and effectively run two type checkers in parallel. Which, on second though, you could run the fast one then the slow one. Perhaps that's an option. > I would personally be very happy to use a significantly slimmed down subset of TypeScript if it provided a 62x performance improvement. Slow type checking is currently the main drawback of TypeScript development in large projects. We all think that until the slimmed down subset doesn't work with our favorite libraries. Sure, there may be people who use no dependencies, but I'd bet that there's sophisticated types in some very popular libraries that even low dependency programmers use.