JavaScript中實作Map的範例程式碼_javascript技巧

不廢話了，直接貼程式碼了。

代碼一：

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) {
    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,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
   * @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;
  };
  /**
   * 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;
  };
  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;
  };
}

代碼二：

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);
}

以上內容透過兩段程式碼給大家分享了JavaScript中實現Map，希望大家喜歡。