[aero142]

I recently added Flow Type to a Javascript project and it changed my opinion on this debate. I realized that I really don't care about static vs dynamic typing. What I care about is a hierarchy of the ways that my code can be more likely correct. Given the same level of verification, integration tests and are worse than unit tests are worse than runtime checks are worse than compile time checks. There may be cases where static typing makes code more performant, but I usually care a lot more about development speed and correctness. In this world, I just want a way of verifying my code as quickly as possible. Gradual typing lets me specify some validations of my code that will run at compile time. This is a huge win for me in both correctness and development speed.

I don't know if we will ever invent the perfect static type system, but I do know that having the ability to specify some types in a pretty good type system, is better than not being able to specify any types.

I'm convinced that a language with a progressive type system is strictly better than one without. Therefor, any debate that compares static vs dynamic, instead of static vs progressive is not interesting to me.