javascript - 根据给定条件创建嵌套的 json 对象

Question

我有一个平面列表(对象数组)，如下一个:

var myList = [
  {id:1, name:"ABC", type:"level_1"},
  {id:2, name:"XYZ", type:"level_1"},
  {id:1, name:"ABC_level 2", type:"level_2", level_one_id:1},
  {id:2, name:"XYZ_level 2", type:"level_2", level_one_id:2},
  {id:1, name:"ABC_level 3", type:"level_3", level_two_id:1},
  {id:2, name:"XYZ_level 3", type:"level_3", level_two_id:2},
];

然后，我必须以可以创建层次结构的方式对它们进行分组(我尝试在下面的代码行中这样做):

var myList = [
  {id:1, name:"ABC", type:"level_1"},
  {id:2, name:"XYZ", type:"level_1"},
  {id:1, name:"ABC_level 2", type:"level_2", level_one_id:1},
  {id:2, name:"XYZ_level 2", type:"level_2", level_one_id:2},
  {id:1, name:"ABC_level 3", type:"level_3", level_two_id:1},
  {id:2, name:"XYZ_level 3", type:"level_3", level_two_id:2},
];

var myNestedList = {
    levels: []
};
    
//-----------pushing level1----------

myList.forEach((res => {
    if (res.type == "level_1") {
        myNestedList.levels.push(res);
    }
}));

//-----------pushing level 2---------

myNestedList.levels.forEach((res) => {
    myList.forEach((val) => {
        if (val.type == "level_2" && val.level_one_id == res.id) {
            res["level_2"] = [] || res["level_2"];
            res["level_2"].push(val);
        }
    })
})
    
//-----------pushing level 3---------
    
myNestedList.levels.forEach((res) => {
    res["level_2"].forEach((val) => {
        myList.forEach((lastlevel) => {
            if (lastlevel.type == "level_3" && lastlevel.level_two_id == val.id) {
                val["level_3"] = [] || val["level_3"];
                val["level_3"].push(lastlevel);
            }
        })
    })
})

console.log(myNestedList);

虽然我能够实现这个结果，但我相信这段代码可以更精确、更有意义。我们可以在这里使用 lodash 并缩短这段代码吗？

任何帮助将不胜感激。谢谢!

Answer 1

您可以为对象获取一个虚拟的唯一 id 并引用其父对象，并将这些项目收集在树中。

这种方法也适用于未排序的数据。

var data = [{ id: 1, name: "ABC", type: "level_1" }, { id: 2, name: "XYZ", type: "level_1" }, { id: 1, name: "ABC_level 2", type: "level_2", level_one_id: 1 }, { id: 2, name: "XYZ_level 2", type: "level_2", level_one_id: 2 }, { id: 1, name: "ABC_level 3", type: "level_3", level_two_id: 1 }, { id: 2, name: "XYZ_level 3", type: "level_3", level_two_id: 2 }],
    tree = function (data) {
        var t = {};
        data.forEach(o => {
            var level = o.type.match(/\d+$/)[0],
                parent = o[Object.keys(o).filter(k => k.startsWith('level_'))[0]] || 0,
                parentId = `${level - 1}.${parent}`,
                id = `${level}.${o.id}`,
                children = `level_${level}`;

            Object.assign(t[id] = t[id] || {}, o);
            t[parentId] = t[parentId] || {};
            t[parentId][children] = t[parentId][children] || [];
            t[parentId][children].push(t[id]);
        });
        return t['0.0'].level_1;
    }(data);

console.log(tree);

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