DAY(20*O(1)+2*O(1)) | Commented 👍| Eassiest ✅
The given code defines a function called flat using arrow function syntax. This function takes in two parameters: arr, which is an array, and n, which represent
The given code defines a function called `flat` using arrow function syntax. This function takes in two parameters: `arr`, which is an array, and `n`, which represents the depth level until which the array should be flattened.\n\nThe code uses a ternary operator to check if the value of `n` is truthy. If `n` is truthy (non-zero), it indicates that the array needs to be flattened to a certain depth. Otherwise, if `n` is falsy (zero or undefined), it indicates that the array should be flattened completely.\n\nThe implementation uses the `reduce` method on the `arr` array to flatten it. Inside the `reduce` callback function, the code checks if the current element (`next`) is an array using the `Array.isArray` method.\n\nIf `next` is an array, it recursively calls the `flat` function with the nested array (`next`) and decreases the value of `n` by 1. The spread operator (`...`) is used to spread the flattened nested array elements into the `temp` array.\n\nIf `next` is not an array, it means it\'s a non-nested element, so the code directly pushes it into the `temp` array.\n\nFinally, the callback function returns the `temp` array, which is the accumulated result at each step of the `reduce` operation.\n\nOutside the ternary operator, if `n` is truthy, the function returns the flattened array generated through the `reduce` operation. Otherwise, it returns the original `arr` without any flattening.\n\nHere\'s an example to illustrate the behavior of the `flat` function:\n\n```javascript\nconst array = [1, [2, [3, 4, [5, 6]]], 7];\n\nconsole.log(flat(array, 0));\n// Output: [1, [2, [3, 4, [5, 6]]], 7]\n\nconsole.log(flat(array, 1));\n// Output: [1, 2, [3, 4, [5, 6]], 7]\n\nconsole.log(flat(array, 2));\n// Output: [1, 2, 3, 4, [5, 6], 7]\n\nconsole.log(flat(array, 3));\n// Output: [1, 2, 3, 4, 5, 6, 7]\n\nconsole.log(flat(array));\n// Output: [1, 2, 3, 4, 5, 6, 7] (complete flattening)\n```\n\nIn the above example, the `array` contains nested arrays. By passing different values of `n` to the `flat` function, you can control the depth of flattening.\n\n***Here is the code to the current problem:-***\n\n```\n\nvar flat = (arr, n) =>\n    n ?\n        arr.reduce(\n            (temp, next) => (\n                Array.isArray(next) ?\n                    temp.push(...flat(next, n - 1)) :\n                    temp.push(next),\n                temp\n            ),\n            []\n        ) :\n        arr;\n```
['Array', 'JavaScript']