js实现字典结构

	//字典数据结构
	function Dictionary(){
		this.items = {};
		//检查是否有某一个键
		this.has = function(key){
			return this.items.hasOwnProperty(key);
		}
		//为字典添加某一个值
		this.set = function(key,val){
			this.items[key] = val;
		}
		//删除某一个键
		this.delete = function(key){
			if(this.has(key)){
				delete this.items[key];
				return true;
			}
			return false;
		}
		//查找某一特定项
		this.get = function(key){
			return this.has(key) ? this.items[key] : undefined; 
		}
		//返回字典中的所有值
		this.values = function(){
			var res = [];
			for(var prop in this.items){
				if(this.has(prop)){
					res.push(this.items[prop]);
				}
			}
			return res;
		}
		//清空字典
		this.clear = function(){
			this.items = {};
		}
		//获取字典的长度
		this.size = function(){
			return Object.keys(this.items).length;
		}
		//获取字典所有的键
		this.keys = function(){
			return Object.keys(this.items);
		}
		//返回字典本身
		this.getItems = function(){
			return this.items;
		}
	}
    //使用方法
	var dictionary = new Dictionary();
    dictionary.set('Gandalf', '[email protected]');
    dictionary.set('John', '[email protected]');
    dictionary.set('Tyrion', '[email protected]');
    console.log(dictionary.has('Gandalf'));
    console.log(dictionary.size());
    console.log(dictionary.keys());
    console.log(dictionary.values());
    console.log(dictionary.getItems());
    console.log(dictionary.get('Tyrion'));
    dictionary.delete('John');
    console.log(dictionary.keys());
	console.log(dictionary.values()); 
	console.log(dictionary.getItems());