How to implement Map using Array and Object in JavaScript_javascript skills

The example in this article describes the method of using Array and Object to implement Map in JavaScript. Share it with everyone for your reference. The details are as follows:

Yesterday, I suddenly saw a Map implemented by others using JavaScript and it was very good. However, I found that there were problems with some methods. I improved it by adding remove, indexOf, values, clear and other methods.

/**
 * @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;
  }
}

I hope this article will be helpful to everyone’s JavaScript programming design.