It's not different from Elm. My point was that Elm forces you to do it, there's no way around. With Javascript+Flow or TypeScript, you need discipline to end up

It's not different from Elm. My point was that Elm forces you to do it, there's no way around. With Javascript+Flow or TypeScript, you need discipline to end up with code that is as reliable as Elm. Me, personally, I take short-cuts when I'm pressed for time, stressed, or in a bad mood (which happens more often than I'd like to admit). I can always improve the code later (which turns into never). In Elm, I can't cut corners (as easily). This makes me write better code using Elm, which in turn makes me happier. You --can-- get the same experience with Javascript, but it does require more from you, the developer.