JS Practice — Built-in Objects

Array.prototype.toReversed() — new reference

📖 Usage Example

const arr = [1, 2, 3]
arr.reverse()        // mutates: arr is now [3, 2, 1]
const r = [1,2,3].toReversed()  // safe: original preserved

Prefer toReversed() over reverse() in functional pipelines to avoid mutation side effects.

Array.prototype.toReversed() — reference identity

toReversed() always returns a new array object. This means arr.toReversed() !== arr is always true, even if the array has one element or is empty.

Challenge: Implement toReversedReturnsNew(arr) that returns true if the result of arr.toReversed() is a different reference than arr.

toReversedReturnsNew([1, 2, 3]) // → true

💡 Hints (2)

• `!==` checks reference identity — two arrays with the same values are still different objects.
• Compare with `reverse()`: `arr.reverse() === arr` would be `true` since it mutates in place.