JS Practice — Built-in Objects

Array.prototype.flat() — configurable depth

📖 Usage Example

const arr = [[1, 2], [3, [4, 5]]]
arr.flat(1)  // → [1, 2, 3, [4, 5]]
arr.flat(2)  // → [1, 2, 3, 4, 5]

Tune the depth argument of flat() to precisely control how many nesting levels collapse.

Array.prototype.flat() — dynamic depth

The depth argument to flat() can be any non-negative integer or Infinity. This lets you build configurable flattening utilities.

Challenge: Implement flatToDepth(arr, depth) that wraps arr.flat(depth).

flatToDepth([1, [2, [3]]], 1) // → [1, 2, [3]]
flatToDepth([1, [2, [3]]], 2) // → [1, 2, 3]

💡 Hints (2)