Group array items using object will more than 2 elements

Question

I found this solution for the kind of problem I'm trying to solve here

The only difference is that my array of object has more than 2 elements and the result wanted is similar to the solution but with all the elements

{
    "group": "one",
    "color": ["red", "green", "black"],
    "size": ["big"],
    "date": ["11/08/2018"]
}

So I've been repeating the .map() to get all my values to show but I feel that I shouldn't ...
Can someone please help me with and simpler and better option?

var db = [{"Record":{"id":"26","cost_center":"15073 DC1 M8 - Filmatic","batch_no":"367746","item_code":"12583","description":"LF Fruited Guava (2x6)x15"}},{"Record":{"id":"29","cost_center":"15073 DC1 M8 - Filmatic","batch_no":"367749","item_code":"12583","description":"LF Fruited Guava (2x6)x15"}},{"Record":{"id":"36","cost_center":"15093 DC1 M10 - CornerPot Machi","batch_no":"367756","item_code":"12256","description":"PROMO CP LF SaltedCar w H"}}];

var myArray = [];
for (var i in db) {
    if (db.hasOwnProperty(i)) {
        myArray.push(db[i].Record);
    }
}

var res = myArray.reduce(function(res, elem) {
    if (res.indexOf(elem.cost_center) === -1) {
        res.push(elem.cost_center);
    }
    return res;
}, []).map(function(machine) {
    return {
        cost_center: machine,
        batch_no: myArray.filter(function(_el) {
            return _el.cost_center === machine;
        }).map(function(_el) { return _el.batch_no; }),
        item_code: myArray.filter(function(_el) {
            return _el.cost_center === machine;
        }).map(function(_el) { return _el.item_code; }),
        description: myArray.filter(function(_el) {
            return _el.cost_center === machine;
        }).map(function(_el) { return _el.description; })
    }
});

console.log(res);

where do you get the additional properties, like `size` and `date`, from? — Nina Scholz, Aug 11 '17 at 10:08
@NinaScholz I updated the question with an example, I would like to group by cost_center — Jonathan, Aug 11 '17 at 10:28
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/151713/discussion-between-jonathan-and-nina-scholz). — Jonathan, Aug 11 '17 at 10:55

Nina Scholz · Accepted Answer · 2017-08-11T11:30:41.350

For the later added code, you could use a hash table, where you collect all objects with the same cost_center and use another array for collecting the values of the properties, like batch_no, item_code and description.

var db = [{ Record: { id: "26", cost_center: "15073 DC1 M8 - Filmatic", batch_no: "367746", item_code: "12583", description: "LF Fruited Guava (2x6)x15" } }, { Record: { id: "29", cost_center: "15073 DC1 M8 - Filmatic", batch_no: "367749", item_code: "12583", description: "LF Fruited Guava (2x6)x15" } }, { Record: { id: "36", cost_center: "15093 DC1 M10 - CornerPot Machi", batch_no: "367756", item_code: "12256", description: "PROMO CP LF SaltedCar w H" } }],
    keys = ["batch_no", "item_code", "description"],
    hash = Object.create(null),
    result = [];

db.forEach(function (o) {
    if (!hash[o.Record.cost_center]) {
        hash[o.Record.cost_center] = { cost_center: o.Record.cost_center };
        keys.forEach(function (k) {
            hash[o.Record.cost_center][k] = [o.Record[k]];
        });
        result.push(hash[o.Record.cost_center]);
        return;
    }
    keys.forEach(function (k) {
        hash[o.Record.cost_center][k].push(o.Record[k]);
    });
});

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Group array items using object will more than 2 elements

1 Answers1