javaScript实现一个队列的方法

class Queue{
  constructor(){
    this.count = 0;//记录队列的数量
    this.lowestCount = 0;//记录当前队列头部的位置
    this.items = [];//用来存储元素。
  }
}

 enqueue(element){
    this.items[this.count] = element;
    this.count++;
  }

dequeue(){
    if(this.isEmpty()){
      return 'queue is null';
    }
    let resulte = this.items[this.lowestCount];
    delete this.items[this.lowestCount];
    this.lowestCount++;
    return resulte;
  }

  peek(){
    return this.items[this.lowestCount];
  }

  isEmpty(){
    return this.count - this.lowestCount === 0;
  }

  clear(){
    this.count = 0;
    this.lowestCount = 0;
    this.items = [];
  }

 size(){
    return this.count - this.lowestCount;
  }

toString(){
    if(this.isEmpty())return "queue is null";
    let objString = this.items[this.lowestCount];
    for(let i = this.lowestCount+1; i < this.count;i++){
      objString = `${objString},${this.items[i]}`;
    }
    return objString;
  }

class Queue{
  constructor(){
    this.count = 0;//记录队列的数量
    this.lowestCount = 0;//记录当前队列顶部的位置
    this.items = [];//用来存储元素。
  }
  enqueue(element){
    this.items[this.count] = element;
    this.count++;
  }
  dequeue(){
    if(this.isEmpty()){
      return 'queue is null';
    }
    let resulte = this.items[this.lowestCount];
    delete this.items[this.lowestCount];
    this.lowestCount++;
    return resulte;
  }
  peek(){
    return this.items[this.lowestCount];
  }
  isEmpty(){
    return this.count - this.lowestCount === 0;
  }
  size(){
    return this.count - this.lowestCount;
  }
  clear(){
    this.count = 0;
    this.lowestCount = 0;
    this.items = [];
  }
  toString(){
    if(this.isEmpty())return "queue is null";
    let objString = this.items[this.lowestCount];
    for(let i = this.lowestCount+1; i < this.count;i++){
      objString = `${objString},${this.items[i]}`;
    }
    return objString;
  }
}