js实现的map方法

    /**
     *
     * 描述：js实现的map方法
     * @returns {Map}
     */
    function Map(){
     var struct = function(key, value) {
      this.key = key;
      this.value = value;
     };
    // 添加map键值对
     var put = function(key, value){
       for (var i = 0; i < this.arr.length; i++) {
       if ( this.arr[i].key === key ) {
        this.arr[i].value = value;
        return;
       }
      };
      this.arr[this.arr.length] = new struct(key, value);
     };
    //  根据key获取value
     var get = function(key) {
      for (var i = 0; i < this.arr.length; i++) {
       if ( this.arr[i].key === key ) {
        return this.arr[i].value;
       }
      }
     return null;
     };
    //   根据key删除
     var remove = function(key) {
      var v;
      for (var i = 0; i < this.arr.length; i++) {
       v = this.arr.pop();
       if ( v.key === key ) {
        continue;
       }
       this.arr.unshift(v);
      }
     };
    //   获取map键值对个数
     var size = function() {
      return this.arr.length;
     };
    // 判断map是否为空
     var isEmpty = function() {
      return this.arr.length <= 0;
     };
     this.arr = new Array();
     this.get = get;
     this.put = put;
     this.remove = remove;
     this.size = size;
     this.isEmpty = isEmpty;
    }  

<script type="text/javascript">
    var map=new Map();
    map.put("num",1);
    map.put("ss","wss");
    alert(map.size());
    alert(map.get("num"));
    paraArr.remove("num");
    alert(map.size());
    alert(map.get("num"));
</script>