javascript group by 对数据分组

网上找不到js分组的原生态方法，今天有空自己写了个方法，感觉还可以，拿出来分享，望各位读者多多指教。

$scope.groupBy = function (itemlist, gby) {

        var setGroupObj = function (noteObj,rule, gby, gIndex, maxIndex)
        {
            var gname = rule[gby[gIndex]];
            if (gIndex == maxIndex) {
                if (noteObj[gname] == undefined)
                    noteObj[gname] = [];
                if (noteObj[gname].indexOf(rule) < 0) {
                    noteObj[gname].push(rule);
                }
            }
            else {
                if (noteObj[gname] == undefined) {
                    noteObj[gname] = {};
                }
                setGroupObj(noteObj[gname], rule, gby, gIndex + 1, maxIndex);
            }
        }

        var noteObj = {};
        for (var i = 0; i < itemlist.length; i++) {
            setGroupObj(noteObj, itemlist[i], gby, 0, gby.length - 1);
        }


        var getSubInfo = function (note, p, gIndex, maxIndex) {
            var newobj = {}
            newobj.key = p;
            newobj.value = [];
            if (gIndex == maxIndex) {
                for (var k in note) {
                    newobj.value.push(note[k]);
                }
            }
            else {
                for (var k in note[p]) {
                    newobj.value.push(getSubInfo(note[p][k], k, gIndex + 1, maxIndex));
                }
            }
            return newobj;
        }
        var myobj = [];
        for (var p in noteObj) {
            myobj.push(getSubInfo(noteObj, p, 0, gby.length - 1));
        }
        return myobj;
    }
    $scope.groupRules = $scope.groupBy(allrules, ['groupbycolumn1', 'groupbycolumn2']);

其中allrules是要分组的数组，groupbycolumn1,groupbycolumn2是要进行分组的字段名，可以支持多个。

返回的结果是一个分组的对象：

var result={key:'',value:[

{key:'',value:[]},{key:'',value:[]}

]}