js构建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);
    }
  };

  this.arr = new Array();
  this.get = get;
  this.put = put;
  this.remove = remove;
}