JS Practice — Built-in Objects

Array.prototype.forEach() — always returns undefined

📖 Usage Example

const result = [1, 2, 3].forEach(n => n * 2)
console.log(result)  // → undefined

forEach() always returns undefined — use map() instead if you need a new array.

Array.prototype.forEach() — return value

No matter what the callback returns, forEach always returns undefined. This distinguishes it from map, filter, and reduce.

Challenge: Implement forEachReturns(arr) that calls forEach on the array and returns its return value (which will always be undefined).

forEachReturns([1, 2, 3]) // → undefined

💡 Hints (2)