Typed zip functions in TypeScript

typescript-zip.ts

// zip for 2 arrays
function zip2<A, B>(a: A[], b: B[]): Array<[A, B]> {
  return a.map((_, c) => [a, b].map(row => row[c])) as Array<[A, B]>;
}

// zip for any number of arrays
type Zip<T extends unknown[][]> = { [I in keyof T]: T[I] extends (infer U)[] ? U : never }[];
function zip<T extends unknown[][]>(...args: T): Zip<T> {
    return <Zip<T>><unknown>(args[0].map((_, c) => args.map(row => row[c])));
}