Get middle element of the Linked List in Javascript

You can use below code to find middle of Linked List-

/**
 * @param {ListNode} head
 * @return {ListNode}
 */
var middleNode = function(head) {
    let len = 1, index = 1;
    let temp = head;
    let arr = [];
    while(head.next!=null) {
        len++;
        head = head.next;
    }
    let mid = Math.ceil(len/2); 
    if(len%2==0) {
        mid++;
    }
    while(mid>index) {
        temp = temp.next;
        index++;
    }
    return temp;
};