JS Practice — Built-in Objects

Replace Last Element

📖 Usage Example

const arr = ['a', 'b', 'c']
arr.with(-1, 'z')  // → ['a', 'b', 'z']
arr                // → ['a', 'b', 'c']  (unchanged)

Pass a negative index to with() to replace an element counting from the end.

Array.prototype.with — Negative Index

with() supports negative indices. -1 refers to the last element.

Implement replaceFromEnd that replaces the last element of arr with val using arr.with(-1, val).

💡 Hints (2)