Discussion on: Do you use Static Typing in JavaScript?

[Nick Taylor]

I haven't used Flow, but I'm not following your comment. Do you mean that the coerced value 2 from "2" should pass here?

[Meghan (she/her)]

The way that I interpreted this example from their homepage is that the type checker is assuming that n should be a Number since the function uses n * n which is fair, but then the function is called with the String and it says the error is in the function and I believe that the function definition should take precedence on which type is "right".

[Nick Taylor]

Maybe it's not clear on their site., The function definition takes precedence like you thought it should.

Here's the example on their site:

// @flow
function square(n: number): number {
  return n * n;
}

square("2"); // Error!

What they're showing here is that the type checker won't allow you to call the function with a string.