queueImplementation.js

class Node {
    constructor(value) {
      this.value = value;
      this.next = null;
    }
  }
  
  class Queue {
    constructor() {
      this.first = null;
      this.last = null;
      this.length = 0;
    }
    peek() {
      return this.first;
    }
    enqueue(value) {
      const newNode = new Node(value);
      if (this.length === 0) {
        this.first = newNode;
        this.last = newNode;
      } else {
        this.last.next = newNode;
        this.last = newNode;
      }
      this.length++;
      return this;
    }
    dequeue() {
      if (!this.first) {
        return null;
      }
      if (this.first === this.last) {
        this.last = null;
      }
      this.first = this.first.next;
      this.length--;
      return this;
    }
    //isEmpty;
  }
  
  const myQueue = new Queue();
  myQueue.enqueue("Joy");
  myQueue.enqueue("Matt");
  myQueue.enqueue("Pavel");
  myQueue.enqueue("Samir");
  myQueue.dequeue();
  myQueue.peek();
  console.log(myQueue);
  //Joy
  //Matt
  //Pavel
  //Samir