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)])

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]>>>,
]


// ============= Your Code Here =============
declare function PromiseAll<T extends any[]>(values: [...T]): Promise<{
  [k in keyof T]: T[k] extends Promise<infer R> ? R: T[k]
}>