Exhaustive checks example

[ThomWright]

If you add a return type to the function in the Exhaustive checks example, it no longer compiles:

type SupportedValue = "a" | "b"

function doSomething(value: SupportedValue): boolean {
  switch (value) {
    case "a":
      return true
    case "b":
      return true
    default:
      expectType<never>(value)
  }
}

In order for this to work, expectType would need to return never, as in this example.

[blakeembrey]

Oh yeah, I should have actually tested the snippet 😄 I think the correct behavior in this snippet is to return false, and I can add an expectNever function that actually throws and returns never.

[ThomWright]

Great, thank you.

BTW, I've started sprinkling some type assertions around my codebase and it feels very natural. Really enjoying how much easier it makes it to sense-check my types.