Solution.js

/**
 * Definition for singly-linked list.
 * function ListNode(val, next) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.next = (next===undefined ? null : next)
 * }
 */
/**
 * @param {ListNode} head
 * @return {ListNode}
 */
var insertionSortList = function (head) {
    if (head == null || head.next == null) return head;
    let dummy = new ListNode(head.val, head);
    let prev = dummy,
        cur = head;
    while (cur != null) {
        if (prev.val <= cur.val) {
            prev = cur;
            cur = cur.next;
            continue;
        }
        let p = dummy;
        while (p.next.val <= cur.val) {
            p = p.next;
        }
        let t = cur.next;
        cur.next = p.next;
        p.next = cur;
        prev.next = t;
        cur = t;
    }
    return dummy.next;
};