JavaScript中利用Array和Object实现Map的方法
本文实例讲述了JavaScript中利用Array和Object实现Map的方法。分享给大家供大家参考。具体如下：
昨天突然看到以前别人用JavaScript实现的Map感觉很不错，但是发现有个别方法有问题，顺便完善了下，添加了 remove 、indexOf 、values、clear等方法。
/**
* @author blune68
* @version 0.1, 07/27/12
*
*/
function Map(){
this.keys = new Array();
this.data = new Object();
var toString = Object.prototype.toString;
/**
* 当前Map当前长度
*/
this.size = function(){
return this.keys.length;
}
/**
* 添加值
* @param {Object} key
* @param {Object} value
*/
this.put = function(key, value){
if(this.data[key] == null){
this.data[key] = value;
}
this.keys.push(key);
}
/**
* 根据当前key获取value
* @param {Object} key
*/
this.get = function(key){
return this.data[key];
}
/**
* 根据当前key移除Map对应值
* @param {Object} key
*/
this.remove = function(key){
var index = this.indexOf(key);
if(index != -1){
this.keys.splice(index, 1);
}
this.data[key] = null;
}
/**
* 清空Map
*/
this.clear = function(){
for(var i=0, len = this.size(); i < len; i++){
var key = this.keys[i];
this.data[key] = null;
}
this.keys.length = 0;
}
/**
* 当前key是否存在
* @param {Object} key
*/
this.containsKey = function(key){
return this.data[key] != null;
}
/**
* 是否为空
*/
this.isEmpty = function(){
return this.keys.length === 0;
}
/**
* 类型Java中Map.entrySet
*/
this.entrySet = function(){
var size = this.size();
var datas = new Array(size);
for (var i = 0, len = size; i < len; i++) {
var key = this.keys[i];
var value = this.data[key];
datas[i] = {
'key' : key,
'value':value
}
}
return datas;
}
/**
* 遍历当前Map
* var map = new Map();
* map.put('key', 'value');
* map.each(function(index, key, value){
* console.log("index:" + index + "--key:" + key + "--value:" + value)
* })
* @param {Object} fn
*/
this.each = function(fn){
if(toString.call(fn) === '[object Function]'){
for (var i = 0, len = this.size(); i < len; i++) {
var key = this.keys[i];
fn(i, key, this.data[key]);
}
}
return null;
}
/**
* 获取Map中 当前key 索引值
* @param {Object} key
*/
this.indexOf = function(key){
var size = this.size();
if(size > 0){
for(var i=0, len=size; i < len; i++){
if(this.keys[i] == key)
return i;
}
}
return -1;
}
/**
* Override toString
*/
this.toString = function(){
var str = "{";
for (var i = 0, len = this.size(); i < len; i++, str+=",") {
var key = this.keys[i];
var value = this.data[key];
str += key + "=" + value;
}
str = str.substring(0, str.length-1);
str += "}";
return str;
}
/**
* 获取Map中的所有value值(Array)
*/
this.values = function(){
var size = this.size();
var values = new Array();
for(var i = 0; i < size; i++){
var key = this.keys[i];
values.push(this.data[key]);
}
return values;
}
}
希望本文所述对大家的javascript程序设计有所帮助。
赞 (0)