JavaScript 实现Map

var map=new Map();
map.put("a","A");map.put("b","B");map.put("c","C");

map.get("a"); //返回：A

map.entrySet() // 返回Entity[{key,value},{key,value}]

map.containsKey('kevin') //返回:false

function Map() {
this.keys = new Array();
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;
}else{
this.data[key]=this.data[key];
}
return true;
};

/**
* 获取某键相应的值
* @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) {
for(var i=0;i<this.keys.length;i++){
if(key===this.keys[i]){
var del_keys= this.keys.splice(i,1);
for(k in del_keys){
this.data[k] = null;
}
return true;
}
}
return false;
};

/**
* 遍历Map,运行处理函数
*
* @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
* @return entity[{key,value},{key,value}]
*/
this.entrySet = 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[this.keys[i]]
};
}
return entrys;
};

/**
* 推断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;
};

this.containsKey=function(key){
return this.keys.filter(function(v){
if(v===key){
return key;
}
}).length>0;
};
/**
* 重写toString
*/
this.toString = function(){
var s = "{";
for(var i=0;i<this.keys.length;i++){
var k = this.keys[i];
s += k+"="+this.data[k];
if(this.keys.length>i+1){
s+=','
}
}
s+="}";
return s;
};
/**
* 解析字符串到Map
* {a=A,b=B,c=B,}
*/
this.parserStringAndAddMap=function(str){
var count=0;
if(str && str.length>0){
str=str.trim();
var startIndex=str.indexOf("{"),endIndex=str.lastIndexOf("}");
if(startIndex!==-1 && endIndex!==-1){
str=str.substring(startIndex+1,endIndex);
var arrs= str.split(",");
for(var i=0;i<arrs.length;i++){
var kv=arrs[i].trim();
if(kv.length>0 && kv.indexOf("=")!==-1){
var kv_arr=kv.split("=");
if(kv_arr.length==2){
if(this.put(kv_arr[0].trim(),kv_arr[1].trim())){
count++;
}else{
console.error('error: kv:'+kv);
}

}
}
}
}else{
console.log("data error:"+str);
}
}else{
console.log('data is not empty');
}
return count;
};
}