rorate array

function rotateArray(A, K) {
    if (!A.length) return A;
    let index = -1;
    while (++index < K) {
        A.unshift(A.pop());
    }
    return A;
}

[
    rotateArray([3, 8, 9, 7, 6], 3),
    rotateArray([0, 0, 0], 1),
    rotateArray([1, 2, 3, 4], 4),
    rotateArray([], 4),
].join(' | ');

// Java program to rotate an array by 
// d elements 
class RotateArray { 
    /*Function to left rotate arr[] of siz n by d*/
    void leftRotate(int arr[], int d, int n) 
    { 
        /* To handle if d >= n */
        d = d % n; 
        int i, j, k, temp; 
        int g_c_d = gcd(d, n); 
        for (i = 0; i < g_c_d; i++) { 
            /* move i-th values of blocks */
            temp = arr[i]; 
            j = i; 
            while (true) { 
                k = j + d; 
                if (k >= n) 
                    k = k - n; 
                if (k == i) 
                    break; 
                arr[j] = arr[k]; 
                j = k; 
            } 
            arr[j] = temp; 
        } 
    } 
  
    /*UTILITY FUNCTIONS*/
  
    /* function to print an array */
    void printArray(int arr[], int size) 
    { 
        int i; 
        for (i = 0; i < size; i++) 
            System.out.print(arr[i] + " "); 
    } 
  
    /*Fuction to get gcd of a and b*/
    int gcd(int a, int b) 
    { 
        if (b == 0) 
            return a; 
        else
            return gcd(b, a % b); 
    } 
  
    // Driver program to test above functions 
    public static void main(String[] args) 
    { 
        RotateArray rotate = new RotateArray(); 
        int arr[] = { 1, 2, 3, 4, 5, 6, 7 }; 
        rotate.leftRotate(arr, 2, 7); 
        rotate.printArray(arr, 7); 
    } 
}