如何把数组中的多个对象划分成树形结构

types = ['a1', 'b1'];
var liList = [
{
name: 'a1',
tags: ['a1', 'a2']
},
{
name: 'a1',
tags: ['a1', 'a3']
},
{
name: 'b1',
tags: ['b1', 'b2']
},
];

var liFunc = function (liList, types) {
$.each(types, function (i, type) {
liTree(liList, type.tags.concat());
});
};

var liTree = function (list, tags) {
if (tags.length > 0) {
var flag = true;
$.each(list, function (j, node) {
if (node.name === tags[0]) {
node.count++;
flag = false;

            tags.splice(0, 1);
            liTree(node.children, tags);
        }
    });

    if (flag) {
        list.push({
            name: tags[0],
            count: 1,
            children: []
        });

        tags.splice(0, 1);
        liTree(list[list.length - 1].children, tags);
    }
}

};

// 执行
liFunc(liList, types);

// 结果
liList = [
{
name: 'a1',
count: 2,
children: [
{
name: 'a2',
count: 1,
children: []
},
{
name: 'a3',
count: 1,
children: []
}
]
},
{
name: 'b1',
count: 1,
children: [
{
name: 'b2',
count: 1,
children: []
}
]
}
];