Zip

In this medium-level challenge, you'll implement a Zip type that pairs up corresponding elements from two tuples into a tuple of pairs, stopping at the length of the shorter tuple.

[object Object]

type cases = [
  Expect<Equal<Zip<[], []>, []>>,
  Expect<Equal<Zip<[1, 2], [true, false]>, [[1, true], [2, false]]>>,
  Expect<Equal<Zip<[1, 2, 3], ['1', '2']>, [[1, '1'], [2, '2']]>>,
  Expect<Equal<Zip<[], [1, 2, 3]>, []>>,
  Expect<Equal<Zip<[[1, 2]], [3]>, [[[1, 2], 3]]>>,
]

Detailed Explanation

type Zip<T extends any[], U extends any[]> =
  T extends [infer TFirst, ...infer TRest]
    ? U extends [infer UFirst, ...infer URest]
      ? [[TFirst, UFirst], ...Zip<TRest, URest>]
      : []
    : [];

How it works:

• The type simultaneously destructures both input tuples T and U using nested conditional types with infer
• If both tuples have at least one element, the first elements TFirst and UFirst are paired into [TFirst, UFirst], and the result is prepended to the recursive zip of the remaining elements TRest and URest
• If either tuple is empty (either T or U cannot be destructured), the recursion returns an empty tuple [], naturally handling tuples of different lengths by stopping at the shorter one
• For example, Zip<[1, 2, 3], ['1', '2']> pairs 1 with '1' and 2 with '2', then stops because U is exhausted, producing [[1, '1'], [2, '2']]

This challenge helps you understand parallel tuple traversal and recursive type pairing, and how to apply these concepts in real-world scenarios.