[TS] Void function interop

[doasync]

Use case:

  type voidFn = () => void
  const fn = (callback: voidFn) => {
    if(callback) callback()
  }
  const voidEvent: Event<void> = createEvent();
  fn(voidEvent); // TS2345: Argument of type 'Event ' is not assignable to parameter of type 'voidFn'.

This PR adds void function interop:

  const voidFn: () => void = createEvent<void>()
  const voidFn1: () => void = createEvent<undefined>()
  const voidFn2: () => void = createEvent<any>()

  const event1 = createEvent<undefined>()
  event1()
  const event2 = createEvent<any>()
  event2()

The only weak spot is the text of the message:

  const event1 = createEvent<number>()
  event1() /* Error
    The 'this' context of type 'void' is not assignable to method's 'this' of type '"Error:
	Expected 1 argument, but got 0"'.
  */

All tests pass!

[zerobias]

Tests indeed failed

[zerobias]

What is this?

[doasync]

"this" is a type of context, it is void by default

[zerobias]

What is `Error: Expected 1 argument, but got 0`?

[doasync]

It's just a text to show in the error message

[doasync]

According to tests, it will be shown only if Event expects an argument, but no parameters given.

[doasync]

It is important to put "this" overload after the first one to keep this kind of messages right.

[doasync]

I've updated the snapshot, tests pass

[zerobias]

Interesting solution, okay, lets try it. Thanks! 👍