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;
}