Last of Array

In this medium-level challenge, you'll implement a generic Last<T> that extracts the type of the last element from an array.

Medium

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

Change the following code to make the test cases pass (no type check errors).

Video Walkthrough

type Last<T extends unknown[]> = T extends [...infer _Rest, infer Last]
  ? Last
  : never

How it works:

First we constrain the type T to be an array with extends unknown[]
T extends [...infer _Rest, infer Last] matches the array type and captures the last element's type
? Last returns the last element's type if the array is not empty
we return never if the array is empty

This challenge helps you understand array type operations and how to apply this concept in real-world scenarios.