javascript--行列

function Queue() {
	let items = []
	
    //    
	this.enqueue = function(element) {
		items.push(element)
	}
				
	//   
	this.dequeue = function() {
		return items.shift();
	}
				
	//     
	this.front = function() {
		return items[0]
	}
				
	//  
	this.isEmpty = function() {
		return items.length == 0
	} 
				
	//  
	this.print = function() {
		console.log(items.toString());
	}
}