text: class Queue
  {
  	constructor()
  	{
  		this.queue = [];
  	}
  }
  
  Queue.prototype.isEmpty = function(){
  	return this.queue.length > 0 ? false : true;
  };
  
  Queue.prototype.peek = function(){
  	if(this.queue.length == 0)
  		return null;
  	
  	return this.queue[0];
  };
  
  Queue.prototype.enqueue = function(value){
  	this.queue.push(value);
  };
  
  Queue.prototype.dequeue = function(){
  	const removed = this.queue.shift();
      return removed ? removed : null;
  };
  
  Queue.prototype.toString = function(char = ','){
  	return this.queue.join(char);
  };
  
  