The rotate function takes two arguments, nums and k. nums is an array of numbers, and k is the number of positions to rotate the array by. The rotate function loops through each number in the nums array, and assigns the corresponding number from arr to nums[i].
var rotate = function(nums, k) {
let arr = [];
for (let i = 0; i < nums.length; i++) {
let index = (i + k) % nums.length;
arr[index] = nums[i];
}
for (let i = 0; i < nums.length; i++) {
nums[i] = arr[i];
}
};