linked_list.js

class LinkedList {
  constructor() {
    this.head = null;
    this.tail = null;
  }
  
  add(value) {
    const node = { value };
    if (this.tail != null) {
      this.tail.next = node;
      this.tail = node;
    } else {
      this.head = node;
      this.tail = node;
    }
}