当前位置：首页 > news >正文

一个简单的JavaScript Map

news 来源：原创 2024/5/18 14:06:39

用js写了一个Map，带遍历功能，请大家点评下啦。

//map.js

Array.prototype.remove = function(s) {
	for (var i = 0; i < this.length; i++) {
		if (s == this[i])
			this.splice(i, 1);
	}
}

/**
 * Simple Map
 * 
 * 
 * var m = new Map();
 * m.put('key','value');
 * ...
 * var s = "";
 * m.each(function(key,value,index){
 * 		s += index+":"+ key+"="+value+"\n";
 * });
 * alert(s);
 * 
 * @author dewitt
 * @date 2008-05-24
 */
function Map() {
	/** 存放键的数组(遍历用到) */
	this.keys = new Array();
	/** 存放数据 */
	this.data = new Object();
	
	/**
	 * 放入一个键值对
	 * @param {String} key
	 * @param {Object} value
	 */
	this.put = function(key, value) {
		if(this.data[key] == null){
			this.keys.push(key);
		}
		this.data[key] = value;
	};
	
	/**
	 * 获取某键对应的值
	 * @param {String} key
	 * @return {Object} value
	 */
	this.get = function(key) {
		return this.data[key];
	};
	
	/**
	 * 删除一个键值对
	 * @param {String} key
	 */
	this.remove = function(key) {
		this.keys.remove(key);
		this.data[key] = null;
	};
	
	/**
	 * 遍历Map,执行处理函数
	 * 
	 * @param {Function} 回调函数 function(key,value,index){..}
	 */
	this.each = function(fn){
		if(typeof fn != 'function'){
			return;
		}
		var len = this.keys.length;
		for(var i=0;i<len;i++){
			var k = this.keys[i];
			fn(k,this.data[k],i);
		}
	};
	
	/**
	 * 获取键值数组(类似Java的entrySet())
	 * @return 键值对象{key,value}的数组
	 */
	this.entrys = function() {
		var len = this.keys.length;
		var entrys = new Array(len);
		for (var i = 0; i < len; i++) {
			entrys[i] = {
				key : this.keys[i],
				value : this.data[i]
			};
		}
		return entrys;
	};
	
	/**
	 * 判断Map是否为空
	 */
	this.isEmpty = function() {
		return this.keys.length == 0;
	};
	
	/**
	 * 获取键值对数量
	 */
	this.size = function(){
		return this.keys.length;
	};
	
	/**
	 * 重写toString 
	 */
	this.toString = function(){
		var s = "{";
		for(var i=0;i<this.keys.length;i++,s+=','){
			var k = this.keys[i];
			s += k+"="+this.data[k];
		}
		s+="}";
		return s;
	};
}


function testMap(){
	var m = new Map();
	m.put('key1','Comtop');
	m.put('key2','南方电网');
	m.put('key3','景新花园');
	alert("init:"+m);
	
	m.put('key1','康拓普');
	alert("set key1:"+m);
	
	m.remove("key2");
	alert("remove key2: "+m);
	
	var s ="";
	m.each(function(key,value,index){
		s += index+":"+ key+"="+value+"\n";
	});
	alert(s);
}

　　//testMap.htm

<html>
<head>
<title>Test Map</title>
<script language="javascript" src="map.js">
</script>
</head>
<body>
<input type="button" value="test" οnclick="testMap()">
</body>
</html>