Найти цикл в односвязном списке (@MrMeison)

findCircle.js

 const node1 = {};
 const node2 = {};
 const node3 = {};
 const node4 = {};
 const node5 = {};
 
 node1.next = node2;
 node2.next = node3;
 node3.next = node4;
 node4.next = node5;
 node5.next = node1;
 
 
 const findCircle = (node) => {
    if (node.next && node.next.next) {
    var hare = node.next;
    var tortoise = node.next.next;
    while (hare !== tortoise) {
        hare = hare.next;
        if (!hare) return false;
        tortoise = tortoise.next;
      if (tortoise.next && tortoise.next.next) {
        tortoise = tortoise.next.next;
      } else {
        return false;
      }
    }
  } else {
    return false;
  }
  return true;
}

console.log(findCircle(node1));