数组对象分类个数js

<script type="text/javascript">
$(function(){
var aaa = [
{"task1":"zhnagsan","age":"25","subname":"haha","nodenum":1},
{"task1":"zhnagsan1","age":"253","subname":"haha","nodenum":1},
{"task1":"zhnagsan2","age":"28","subname":"haha","nodenum":2},
{"task1":"zhnagsan2","age":"25","subname":"haha","nodenum":2},
{"task1":"zhnagsan2","age":"2j","subname":"haha","nodenum":2},
{"task1":"zhnagsan2","age":"25","subname":"haha","nodenum":2},
{"task1":"zhnagsan2","age":"25","subname":"haha","nodenum":2},
{"task1":"zhnagsan2","age":"25","subname":"haha","nodenum":3},
{"task1":"zhnagsan2","age":"25","subname":"haha","nodenum":2},
]function conut(arr,item,pro){
var counts = 0;
arr.map(function(a){
if(a[item]== pro){
counts ++;
}
})
return {
nums:counts,
};
}
console.log(conut(aaa,"age",25))})
</script>