Converting flat JSON to nested using underscore js

Question

I'm querying some data with a couple of joins and it returns me a flat JSON Object. What I want to do is create a proper hierarchy for JSON. I explored and found out about Underscore.js after studying some more, It looked really complicated to convert it.

Below is what raw query data looks like:

"data": [
    {
        "Building_Id": 1,
        "Building_Address": "i-9 ISLAMABAD",
        "Floor_Id": 1,
        "Floor_Name": "Ground",
        "Room_Id": 1,
        "Room_Name": "Bedroom"
    },
    {
        "Building_Id": 1,
        "Building_Address": "i-9 ISLAMABAD",
        "Floor_Id": 1,
        "Floor_Name": "Ground",
        "Room_Id": 2,
        "Room_Name": "TV Lounge"
    },
    {
        "Building_Id": 1,
        "Building_Address": "i-9 ISLAMABAD",
        "Floor_Id": 3,
        "Floor_Name": "1st Floor",
        "Room_Id": 3,
        "Room_Name": "Dining Room"
    },
    {
        "Building_Id": 2,
        "Building_Address": "G-10 ISLAMABAD",
        "Floor_Id": 4,
        "Floor_Name": "Ground",
        "Room_Id": 4,
        "Room_Name": "Bedroom"
    }
]

How I want it to be:

 "data": [
    {
        "Building_Id": 1,
        "Building_Address": "i-9 ISLAMABAD",
        "Floors": [{
                  "Floor_Id": 1,
                  "Floor_Name: "Ground",
                  "Rooms" : [{
                            "Room_Id": 1,
                            "Room_Name": "Bedroom"},
                            {
                            "Room_Id": 2,
                            "Room_Name": "TV Lounge"}
                            }]
                   },
                  "Floor_Id": 3,
                  "Floor_Name: "1st Floor",
                  "Rooms" : [{
                            "Room_Id": 3,
                            "Room_Name": "Dining Room"
                            }]

    }]

Answer 1

Here's one way to do it using underscore.js:

var flatData = {
 "data": [
    {
        "Building_Id": 1,
        "Building_Address": "i-9 ISLAMABAD",
        "Floor_Id": 1,
        "Floor_Name": "Ground",
        "Room_Id": 1,
        "Room_Name": "Bedroom"
    },
    {
        "Building_Id": 1,
        "Building_Address": "i-9 ISLAMABAD",
        "Floor_Id": 1,
        "Floor_Name": "Ground",
        "Room_Id": 2,
        "Room_Name": "TV Lounge"
    },
    {
        "Building_Id": 1,
        "Building_Address": "i-9 ISLAMABAD",
        "Floor_Id": 3,
        "Floor_Name": "1st Floor",
        "Room_Id": 3,
        "Room_Name": "Dining Room"
    },
    {
        "Building_Id": 2,
        "Building_Address": "G-10 ISLAMABAD",
        "Floor_Id": 4,
        "Floor_Name": "Ground",
        "Room_Id": 4,
        "Room_Name": "Bedroom"
    }
  ]
};

var toNested = function(data) {
  return _.map(_.groupBy(data, 'Building_Id'), function(i) {
    return {
      Building_Id: i[0].Building_Id,
      Building_Address: i[0].Building_Address,
      Floors: _.map(_.groupBy(i, 'Floor_Id'), function(j) {   
        return {
          Floor_Id: j[0].Floor_Id,
          Floor_Name: j[0].Floor_Name,
          Rooms: _.map(j, function(k) {
            return {
              Room_Id: k.Room_Id,
              Room_Name: k.Room_Name
            };
          })
        };
      })
    };
  });
};

var nestedData = {
  "data": toNested(flatData.data)
};

console.log(nestedData);

<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.9.1/underscore-min.js"></script>