[JS] Reverse linked list

reverseLinkedList.js

function reverseLinkedList(head) {
  let prev = null; 
  let cur = head; 
  let next = null; 
  
  while(cur) {
    next = cur.next; 
    cur.next = prev;
    prev = cur;
    cur = next;            
  }
  
  return prev;
}

// ------------------------------------ Test ----------------------------- //
class Node {
  constructor(data) {
    this.data = data;
    this.next = null;  
  }  
}

console.log(reverseLinkedList()); // null
let node1 = new Node(1);
console.log( reverseLinkedList(node1)); // 1
node1 = new Node(1);
let node2 = new Node(2);
node1.next = node2;
console.log(reverseLinkedList(node1)); // 2-1 
node1 = new Node(1);
node2 = new Node(2);
node1.next = node2;
let node3 = new Node(3);
node2.next = node3;
console.log(reverseLinkedList(node1)); //3-2-1
node1 = new Node(1);
node2 = new Node(2);
node1.next = node2;
node3 = new Node(3);
node2.next = node3;
let node4 = new Node(4);
node3.next = node4;
console.log(reverseLinkedList(node1)); //4-3-2-1