fromEntries typing

fromEntries.ts

type Entries<T extends Readonly<Array<readonly [string, any]>>> = {
  [Index in keyof T]: { [K in T[Index][0]]: T[Index][1] }
}[number]

type UnionToIntersection<U> = 
  (U extends any ? (k: U) => void : never) extends ((k: infer I) => void) ? I : never            

const fromEntries = <T extends Readonly<Array<readonly [string, any]>>>(entries: T): UnionToIntersection<Entries<T>> =>
  Object.fromEntries(entries) as any

const b = fromEntries([['a', 'foo'], ['b', 42]] as const)