js写的一个Map

//构造一个Map结构体
function struct(key, value){
this.key = key;
this.value = value;
}
function put(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);
}
function get(key){
for(var i=0; i<this.arr.length; i++){
if(this.arr[i].key == key){
return this.arr[i].value;
}
}
}
function remove(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);
}
}
function size(){
return this.arr.length;
}
function isEmpty(){
return this.arr.length <= 0;
}
function Map(){
this.arr = new Array();
this.get = get;
this.put = put;
this.remove = remove;
this.size = size;
this.isEmpty = isEmpty;
this.sort = sort;
}
function sort(){
}


function main(){
         Map map = new Map();
         map.put(....);
}