如何根据数组中对象的某个属性值生成对应的多个数组

今天有个朋友问了我一个需求，她有个数组，需要根据数组中的type字段生成对应type相同的数组，而这个type是前端界面上动态添加获得的，也不曾有码表。

先上数组

var arr = [
    {regulationsId: 5172, title: "测试111标题2 ", type: 610, state: 1, createdTime: 1530152467000},
    {regulationsId: 5169, title: "测试111标题", type: 610, state: 1, createdTime: 1530085573000},
    {regulationsId: 5170, title: "测试123标题", type: 609, state: 1, createdTime: 1530085687000},
    {regulationsId: 5171, title: "测试1122标题", type: 608, state: 1, createdTime: 1530085750000}
];

可以发现这个需求就是数组的名称要动态生成，奉上代码如下：

var arr = [
    {regulationsId: 5172, title: "测试111标题2 ", type: 610, state: 1, createdTime: 1530152467000},
    {regulationsId: 5169, title: "测试111标题", type: 610, state: 1, createdTime: 1530085573000},
    {regulationsId: 5170, title: "测试123标题", type: 609, state: 1, createdTime: 1530085687000},
    {regulationsId: 5171, title: "测试1122标题", type: 608, state: 1, createdTime: 1530085750000}
];

//先获取一下这个数组中有多少个type
var types = [];
for(var i in arr){
    if(types.indexOf(arr[i].type) === -1){
        types.push(arr[i].type)
    }
}
//一个包含多个list的结果对象
var obj = {};

// 根据type生成多个数组
for(var k in types){
    for(var j in arr){
        if(arr[j].type == types[k]){
            console.log(types[k], ">>>>>>>>>", arr[j])
            obj[types[k]] = obj[types[k]] || [];
            obj[types[k]].push(arr[j])
        }
    }
}
console.log(types)
console.log(obj)

解决方案如上，应该还有高逼格的实现方法，本人愚钝，暂时想到这个方法。