recursion
Intuition\n Describe your first thoughts on how to solve this problem. \n\n# Approach\n Describe your approach to solving the problem. \n\n# Complexity\n- Time 
# Intuition\n<!-- Describe your first thoughts on how to solve this problem. -->\n\n# Approach\n<!-- Describe your approach to solving the problem. -->\n\n# Complexity\n- Time complexity:\n<!-- Add your time complexity here, e.g. $$O(n)$$ -->\n\n- Space complexity:\n<!-- Add your space complexity here, e.g. $$O(n)$$ -->\n\n# Code\n```javascript []\n/**\n * @param {Array} arr\n * @param {number} depth\n * @return {Array}\n */\nvar flat = function (arr, n) {\n  const flatArr = [];\n  if(n< 1){\n    return arr;\n  }\n  for(let i=0;i<arr.length;i++){\n    if(Array.isArray(arr[i])){\n        flatArr.push(...flat(arr[i], n-1))\n    }else{\n        flatArr.push(arr[i])\n    }\n  }\n  return flatArr;\n};\n```
['JavaScript']