Lodash Groupby Key If Exist In Collection

I have below an array { 'sec': '11', 'details': [ { 'id': '1', 'user': 'Me1' }, { 'id': '2', 'uesr': 'Me2' }, { 'id': '3',

Solution 1:

You need a different approach, not grouping, but creating a tree out of the related data.

This solution uses an array with id as key and with parentID as well. The code works with a single loop, because of storing of the relation of children and parent and parent to their children.

How it works:

Basically for every object in the array it takes as well the id for building a new object as the parentID for a new object.

So for example this object

{ id: "6", parentID: "2", user: "Me6" }

it generates in o first with id this property

6: {
    id: "6",
    parentID: "2",
    user: "Me6"
}

and then this property with parentID

2: {
    children: [
        {
            id: "6",
            parentID: "2",
            user: "Me6"
        }
    ]
},

and while all object treated like this, we finally get a tree.

At the end, the children array of the root property is returned.

functiongetTree(data, root) {
    var o = {};
    data.forEach(function (a) {
        if (o[a.id] && o[a.id].children) {
            a.children = o[a.id].children;
        }
        o[a.id] = a;
        o[a.parentID] = o[a.parentID] || {};
        o[a.parentID].children = o[a.parentID].children || [];
        o[a.parentID].children.push(a);
    });
    return o[root].children;
}

var data = { sec: "11", details: [{ id: "1", user: "Me1" }, { id: "2", uesr: "Me2" }, { id: "3", user: "Me3" }, { id: "4", user: "Me4", parentID: "2" }, { id: "5", uesr: "Me5" }, { id: "6", user: "Me6", parentID: "2" }, { id: "7", user: "Me7" }, { id: "8", user: "Me8", parentID: "7" }, { id: "9", user: "Me9", parentID: "7" }], isDisplay: "true" },
    result = { sec: "11", details: getTree(data.details, undefined), isDisplay: "true" };

console.log(result);

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