JS Practice — Built-in Objects

Array.prototype.findLast() — returns undefined when not found

📖 Usage Example

const arr = [1, 2, 3]
arr.findLast(n => n > 10)  // → undefined  (no match)

findLast() returns undefined when no element satisfies the predicate.

Array.prototype.findLast() — no match

Just like find(), findLast() returns undefined when no element satisfies the predicate.

Challenge: Implement findLastNegative(nums) that returns the last negative number, or undefined if none.

findLastNegative([1, -2, 3, -4]) // → -4
findLastNegative([1, 2, 3])      // → undefined

💡 Hints (2)

• `n < 0` excludes zero — use `n <= 0` to include it.
• When no element matches, `findLast()` returns `undefined`, just like `find()`.