18 - flatten

[nitish8899]

index.js

export const flatten = function(arr, depth = 1, result = []) {
  for (let i = 0, length = arr.length; i < length; i++) {
    const value = arr[i];
    if (Array.isArray(value) && depth > 0) {
      flatten(value, depth - 1, result);
    } else {
      result.push(value);
    }
  }
  return result;
};