[Typescript Challenge] 148 Medium - CartesianProduct

Given 2 sets (unions), return its Cartesian product in a set of tuples, e.g.

  CartesianProduct<1 | 2, 'a' | 'b'>
  // [1, 'a'] | [2, 'a'] | [1, 'b'] | [2, 'b']

 

Solution:

/* _____________ Your Code Here _____________ */

type CartesianProduct<T, U> = T extends infer T1
  ? U extends infer U1
    ? [T1, U1]
    : never
  : never

/* _____________ Test Cases _____________ */
import type { Equal, Expect } from '@type-challenges/utils'
import { ExpectFalse, NotEqual } from '@type-challenges/utils'

type cases = [
  Expect<Equal<CartesianProduct<1 | 2, 'a' | 'b'>, [2, 'a'] | [1, 'a'] | [2, 'b'] | [1, 'b']>>,
  Expect<Equal<CartesianProduct<1 | 2 | 3, 'a' | 'b' | 'c' >, [2, 'a'] | [1, 'a'] | [3, 'a'] | [2, 'b'] | [1, 'b'] | [3, 'b'] | [2, 'c'] | [1, 'c'] | [3, 'c']>>,
  Expect<Equal<CartesianProduct<1 | 2, 'a' | never>, [2, 'a'] | [1, 'a'] >>,
  Expect<Equal<CartesianProduct<'a', Function | string>, ['a', Function] | ['a', string]>>,
]