JS Practice — Built-in Objects

toString with Nested Arrays

📖 Usage Example

const arr = [1, [2, 3], [4, [5]]]
arr.toString()  // → '1,2,3,4,5'  (recursive flattening)

toString() recursively converts nested arrays, effectively flattening them into the string.

Array.prototype.toString — Nested Arrays

When an array contains nested arrays, toString recursively flattens them into the output string. Each nested array is also comma-joined.

Implement nestedToString which returns the string representation of an array that may contain nested arrays.

💡 Hints (2)