function sortArr(arr, str) {
            var _arr = [],
                _t = [],
                // 临时的变量
                _tmp;
            // 按照特定的参数将数组排序将具有相同值得排在一起
            arr = arr.sort(function (a, b) {
                var s = a[str],
                    t = b[str];

                return s < t ? -1 : 1;
            });

            if (arr.length) {
                _tmp = arr[0][str];
            }
            // 将相同类别的对象添加到统一个数组
            for (var i in arr) {
                if (arr[i][str] === _tmp) {
                    _t.push(arr[i]);
                } else {
                    _tmp = arr[i][str];
                    _arr.push(_t);
                    _t = [arr[i]];
                }
            }
            // 将最后的内容推出新数组
            _arr.push(_t);
            return _arr;
        }
        let arr = [
         { name: "xue", age: "18" }, { name: "zhong", age: "18" }, 
         { name: "han", age: "19" }, { name: "dao", age: "19" }, 
         { name: "xing", age: "19" },{ name: "cheng", age: "19" },
         { name: "feng", age: "20" }, { name: "nian", age: "20" }, 
         { name: "jiang", age: "18" }, { name: "ni", age: "19" }, 
         { name: "xu", age: "20" }, { name: "xiao", age: "18" }
         ]
        let arr2 = sortArr(arr, "age")
        console.log(arr2);

结果：