javascript 单向链表反转 reverse

leetcode:

https://leetcode.com/problems/reverse-linked-list/

/**
 * Definition for singly-linked list.
 * function ListNode(val) {
 *     this.val = val;
 *     this.next = null;
 * }
 */
/**
 * @param {ListNode} head
 * @return {ListNode}
 */
var reverseList = function(head) {
    var prev = null, cur = head, next;
    
    while (cur !== null) {
        next = cur.next;
        head = cur;
        cur.next = prev;
        prev = cur;
        cur = next;
    }
    return head;
};