Refer: Easy - Awaited

Describe

If we have a type which is wrapped type like Promise. How we can get a type which is inside the wrapped type? For example if we have Promise<ExampleType> how to get ExampleType?

Test Cases

code snippetCopytypescript
import { Equal, Expect } from '@type-challenges/utils'

type X = Promise<string>
type Y = Promise<{ field: number }>
type Z = Promise<Promise<string | number>>

type cases = [
  Expect<Equal<MyAwaited<X>, string>>,
  Expect<Equal<MyAwaited<Y>, { field: number }>>,
  Expect<Equal<MyAwaited<Z>, string | number>>,
]

// @ts-expect-error
type error = MyAwaited<number>

Solution

code snippetCopytypescript
type MyAwaited<T extends Promise<any>> = T extends Promise<infer P> ? (P extends Promise<infer K> ? K : P) : never