00020-medium-promise-all.ts

// ============= Test Cases =============
import type { Equal, Expect } from './test-utils'

const promiseAllTest1 = PromiseAll([1, 2, 3] as const)
const promiseAllTest2 = PromiseAll([1, 2, Promise.resolve(3)] as const)
const promiseAllTest3 = PromiseAll([1, 2, Promise.resolve(3)])
const promiseAllTest4 = PromiseAll<Array<number | Promise<number>>>([1, 2, 3])

type cases = [
  Expect<Equal<typeof promiseAllTest1, Promise<[1, 2, 3]>>>,
  Expect<Equal<typeof promiseAllTest2, Promise<[1, 2, number]>>>,
  Expect<Equal<typeof promiseAllTest3, Promise<[number, number, number]>>>,
  Expect<Equal<typeof promiseAllTest4, Promise<number[]>>>
]

// ============= Your Code Here =============
type Awaited<T> = T extends Promise<infer R> ? Awaited<R> : T

declare function PromiseAll<T extends any[]>(
  values: readonly [...T]
): Promise<{
  [P in keyof T]: Awaited<T[P]>
}>