268-if.ts

/**
 * 268 - If
 *
 * Implement the util type `If<C, T, F>` which accepts condition `C`, a truthy value `T`, and a falsy value `F`. `C` is expected to be either `true` or `false` while `T` and `F` can be any type.
 *
 * For example:
 *
 * ```ts
 * type A = If<true, 'a', 'b'>  // expected to be 'a'
 * type B = If<false, 'a', 'b'> // expected to be 'b'
 * ```
 */

/* _____________ Your Code Here _____________ */

type If<C extends boolean, T, F> = C extends true
  ? T
  : F

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

type cases = [
  Expect<Equal<If<true, 'a', 'b'>, 'a'>>,
  Expect<Equal<If<false, 'a', 2>, 2>>,
]

// @ts-expect-error
type error = If<null, 'a', 'b'>