Reference cycles in JavaScript

ref-cycles.js

/**
 * Reference cycles can be hard to detect in normal program logic.
 * It's even harder to print the entire linked list when it has its own item pointing to its first item,
 * thus creating a circular linked list.
 * 
 * However, it looks like V8 has a clever method on printing a circular data structure.
 * 
 * In contrast, a handwritten printing mechanism fails to do so since
 * there is always an item linked to the end of the list. This overflows the stack and
 * crashes the browser. A simple way to deal with this is to make sure that no any other
 * node has been visited or printed more than once. This will technically print all the 
 * list item and once it's back to the first item where it started from it stops right 
 * there because it encounters an already visited/ printed node.
 *
 * Here, I'm giving each item its own unique name, so that I can keep track of the visited
 * nodes while traversing the circular linked list.
 */

printList = (a) => {
  const l = [a.value];
  const visited = new Set([a.name]);
  let next = a.next;
  while (next && !visited.has(next.name)) {
    l.push(next.value);
    visited.add(next.name);
    next = next.next;
  }
  return l;
};
ll = (value, next, name) => ({ value, next, name });

/** Creating 2 lists: a, b via linked list function (FP-based) */
a = ll(2, null, 'a');
b = ll(5, a, 'b');

/** Update a to point to b, to complete a circular linked list */
a.next = b;

console.log('a', printList(a), a);
console.log('b', printList(b), b);