Comment by altschuler

Beyond a certain size and complexity (which is not that much), I find that the argument of typescript (and other typed languages) being less productive than untyped dynamic ones, is not true when you look at it as a whole. It might feel slower, especially to begin with, but once you get used to the language and semantics you save a vast amount of time, by the bugs you _don't_ debug and by not having to jump through the code all the time to find out what that function or module was called or what parameters it accepted. This of course is less true if you're using a lot of untyped packages, but as you said, most do have types either natively or in the DefinitelyTyped project. For most modules it's also feasible to declare the module typings manually, even doing it gradually for the parts that you happen to need at a given time.