Push

Add elements to arrays at the type level with Push! ➕

In this easy-level challenge, you'll implement the generic version of Array.push in TypeScript's type system. This type takes a tuple and an element, returning a new tuple with the element appended to the end.

This challenge reinforces your understanding of the spread operator in tuple types and shows how TypeScript can model array operations at compile time. It's a fundamental building block for more complex array manipulations.

For this challenge, you will need to change the following code to make the tests pass (no type check errors).

type Result = Push<[1, 2], '3'> // [1, 2, '3']

Detailed Explanation

The Push type uses the spread operator to append an element to a tuple.

type Push<T extends unknown[], U> = [...T, U]

How it works:

• T extends unknown[] ensures T is an array type
• [...T, U] spreads all elements of T, then adds U at the end
• The result is a new tuple with U appended

This elegantly models JavaScript's push operation at the type level, maintaining type safety for each element in the resulting tuple. The simplicity of this solution showcases TypeScript's expressive power.