js使用map过滤数组中对象

$(function(){
var users=[
{"name":"nihao","age":20},
{"name":"liming","age":21},
{"name":"zhangsan","age":23},
{"name":"zhaosi","age":25},
]
var admins=[];
users.map(function (track) {
if(track.age > 21){
admins.push(track);
}
});
for(var admin in admins){
alert(admins[admin].name +"="+admins[admin].age)
}
})