It'll work because that's what typescript does, and that's why it needs to be implemented there, also. That's my point. And as far as runtime goes, well, that'

It'll work because that's what typescript does, and that's why it needs to be implemented there, also. That's my point. And as far as runtime goes, well, that's not what typescript does. It's a typical compile-time static type system. Typescript aside, even a javascript-level first-class pattern expression is still extremely useful. I really hope it gets in there soon.