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?
type ExampleType = Promise<string>
type Result = MyAwaited<ExampleType> // string/* _____________ Your Code Here _____________ */
type MyAwaited<T extends Promise<any>> = T extends Promise<infer P>
? P extends Promise<any>
? MyAwaited<P>
: P
: T;
/* _____________ Test Cases _____________ */
import type { Equal, Expect } from '@type-challenges/utils'
type X = Promise<string>
type Y = Promise<{ field: number }>
type Z = Promise<Promise<string | number>>
type Z1 = Promise<Promise<Promise<string | boolean>>>
type cases = [
Expect<Equal<MyAwaited<X>, string>>,
Expect<Equal<MyAwaited<Y>, { field: number }>>,
Expect<Equal<MyAwaited<Z>, string | number>>,
Expect<Equal<MyAwaited<Z1>, string | boolean>>,
]
// @ts-expect-error
type error = MyAwaited<number>