How to use assertion in destructuring syntax?

Question

In Typescript, how can I use assertion in destructuring?

type StringOrNumber = string | number

const obj = {
  foo: 123 as StringOrNumber
}

const { foo } = obj

I didn't find a convenient way to add number type assertion on const foo. Two workarounds are:

// A:
const { foo } = obj as { foo: number }

// B:
const { foo: foo2 } = obj

const foo = <number>foo2

The first is a burden to rewrite the obj's type when its type is nested and complicated. The second seems weird. I'm assuming such a syntax like:

const { <number>foo } = obj

can absolutely help us asserting the type from nested and complicated destructuring.

Answer 1

According to the documentation, there is no way for casting the type right when destructuring. Apparently, there are no workarounds other than those that you provided.