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>

　由于项目组要使用eacharts,然后自己随便封装了下