[Typescript] 21. Medium - Last of Array

TypeScript 4.0 is recommended in this challenge

Implement a generic Last<T> that takes an Array T and returns its last element.

For example

type arr1 = ['a', 'b', 'c']
type arr2 = [3, 2, 1]

type tail1 = Last<arr1> // expected to be 'c'
type tail2 = Last<arr2> // expected to be 1

 

/* _____________ Your Code Here _____________ */

type Last<T extends any[]> = T extends [...(infer RT), infer Last] ? Last: never;


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

type cases = [
  Expect<Equal<Last<[3, 2, 1]>, 1>>,
  Expect<Equal<Last<[() => 123, { a: string }]>, { a: string }>>,
]