Grouping multi dimensional array by two values

Question

I am creating inbox, I am retrieving messages from API and I want to group them to create inbox, my problem is I have to group them by 2 values. I have to group them by title (messages are related to products - product title), and also I have to group them by sender ( so I display 2 or more... messages only in case different people sent them)

so my Array look something like:

myMessagesSorted [
  Object {
    "from": "Person 1",
    "fromId": "1QzUz6IJxRhrfesIFmcy1zJ0aFD3",
    "id": 1,
    "message": "This is just sample message",
    "postId": "-MCCl4Z-81uMIPGol-ab",
    "read": 0,
    "time": "Jul 29, 2020, 01:58 PM",
    "title": "Product 1",
  },
  Object {
    "from": "Person 1",
    "fromId": "1QzUz6IJxRhrfesIFmcy1zJ0aFD3",
    "id": 2,
    "message": "This is just sample message 2",
    "postId": "-MCCl4Z-81uMIPGol-ab",
    "read": 0,
    "time": "Jul 29, 2020, 01:58 PM",
    "title": "Product 1",
  },
  Object {
    "from": "Person 1",
    "fromId": "1QzUz6IJxRhrfesIFmcy1zJ0aFD3",
    "id": 3,
    "message": "This is just sample message 3",
    "postId": "-MCCl4Z-81uMIPGol-ab",
    "read": 0,
    "time": "Jul 29, 2020, 01:58 PM",
    "title": "Product 1",
  },
  Object {
    "from": "Person 2",
    "fromId": "1QzUz6IJxRhrfesIFmcy1zJ0aFD3",
    "id": 1,
    "message": "This is just sample message 1",
    "postId": "-MCCl4Z-81uMIPGol-ab",
    "read": 0,
    "time": "Jul 29, 2020, 01:58 PM",
    "title": "Product 1",
  },
  Object {
    "from": "Person 1",
    "fromId": "1QzUz6IJxRhrfesIFmcy1zJ0aFD3",
    "id": 1,
    "message": "This is just sample message 1",
    "postId": "-MCCl4Z-81uMIPGol-ab",
    "read": 0,
    "time": "Jul 29, 2020, 01:58 PM",
    "title": "Product 2",
  },
  Object {
    "from": "Person 1",
    "fromId": "1QzUz6IJxRhrfesIFmcy1zJ0aFD3",
    "id": 2,
    "message": "This is just sample message 2",
    "postId": "-MCCl4Z-81uMIPGol-ab",
    "read": 0,
    "time": "Jul 29, 2020, 01:58 PM",
    "title": "Product 2",
  },
  Object {
    "from": "Person 1",
    "fromId": "1QzUz6IJxRhrfesIFmcy1zJ0aFD3",
    "id": 1,
    "message": "This is just sample message 1",
    "postId": "-MCCl4Z-81uMIPGol-ab",
    "read": 0,
    "time": "Jul 29, 2020, 01:58 PM",
    "title": "Product 3",
  },
  Object {
    "from": "Person 1",
    "fromId": "1QzUz6IJxRhrfesIFmcy1zJ0aFD3",
    "id": 2,
    "message": "This is just sample message 2",
    "postId": "-MCCl4Z-81uMIPGol-ab",
    "read": 0,
    "time": "Jul 29, 2020, 01:58 PM",
    "title": "Product 3",
  },
]

I created little function to group array:

var titles = [];
            var uniquesData = [];
            var index;
            for (var i = 0; i < myMessagesSorted.length; i++) {
                index = titles.indexOf(myMessagesSorted[i].title);
                if (index == -1) {
                    titles.push(myMessagesSorted[i].title);
                    uniquesData.push(myMessagesSorted[i]);
                }
            }
            myMessagesGrouped = uniquesData;

Here I group them by title (product name)... Problem is that for "Product 1" from array I received messages from two different people (Person 1 and Person 2)... so in this case I cannot reply to two different people.

If I group the by from... then it is opposite problem... I see 2 different messages for the same product fine, but if the same person sent message for some other product it is skipped there... :

var titles = [];
            var uniquesData = [];
            var index;
            for (var i = 0; i < myMessagesSorted.length; i++) {
                index = titles.indexOf(myMessagesSorted[i].from);
                if (index == -1) {
                    titles.push(myMessagesSorted[i].from);
                    uniquesData.push(myMessagesSorted[i]);
                }
            }
            myMessagesGrouped = uniquesData;

Ideally I need grouped array like:

array [
  Object {
    "from": "Person 1",
    "fromId": "1QzUz6IJxRhrfesIFmcy1zJ0aFD3",
    "id": 1,
    "message": "This is just sample message",
    "postId": "-MCCl4Z-81uMIPGol-ab",
    "read": 0,
    "time": "Jul 29, 2020, 01:58 PM",
    "title": "Product 1",
  },
  Object {
    "from": "Person 2",
    "fromId": "1QzUz6IJxRhrfesIFmcy1zJ0aFD3",
    "id": 1,
    "message": "This is just sample message 1",
    "postId": "-MCCl4Z-81uMIPGol-ab",
    "read": 0,
    "time": "Jul 29, 2020, 01:58 PM",
    "title": "Product 1",
  },
  Object {
    "from": "Person 1",
    "fromId": "1QzUz6IJxRhrfesIFmcy1zJ0aFD3",
    "id": 1,
    "message": "This is just sample message 1",
    "postId": "-MCCl4Z-81uMIPGol-ab",
    "read": 0,
    "time": "Jul 29, 2020, 01:58 PM",
    "title": "Product 2",
  },
  Object {
    "from": "Person 1",
    "fromId": "1QzUz6IJxRhrfesIFmcy1zJ0aFD3",
    "id": 1,
    "message": "This is just sample message 1",
    "postId": "-MCCl4Z-81uMIPGol-ab",
    "read": 0,
    "time": "Jul 29, 2020, 01:58 PM",
    "title": "Product 3",
  },
]

Grouped by product name, but... only repeated if two or more people enquired about the same product (so people can respond to particular person who sent message)

I assume little change to my little function can do trick...

Thanks!

I'd probably recommend just using [lodash.groupBy](https://lodash.com/docs/4.17.15#groupBy) to group all messages in a "thread". — Petr Bela, Jul 29 '20 at 13:57
Tried, it makes object of arrays, kind of working, but it is not removing duplicate ‘from’. — user13401262, Jul 29 '20 at 19:55
You can define what to *group by*, in your case it seems like both *from* and *title* should be a part of the unique key, so e.g. ```lodash.groupBy(myMessagesSorted, message => `${message.from}_${message.title}`)``` — Petr Bela, Jul 29 '20 at 22:19

Grouping multi dimensional array by two values

0 Answers0