Sort by one value first, then by another

help
1

I want Meteor to sort documents that have a certain value (1) first, and then it should sort them all by date.

Collection.find(selector, {
          sort: {
              starred: -1,
              createdAt: -1
          }
        });

Basically, I want the documents that has starred set to 1 to show up first, no matter when they were made. Then it should sort the rest (starred 0) by date, below the starred ones. How can this be done?

2

You’ll probably require a js sort. You can specify a js sort in minimongo by using a js function as your sort specifier.

3

Do you have any examples?

4

The way to write the sort specifier for minimongo using javascript is in the docs (see sort specifier). As for the algorithm, your compare function would look something like

function(a,b) {
   if (a.starred) return (b.starred)? 0:-1;
   if (b.starred) return 1;
   return a.createdAt - b.createdAt;
}
5

I thought it was supported by minimongo. It wasn’t?

6

use lodash to replace meteor underscore

https://lodash.com/docs/4.17.5#sortBy

7

Thanks for the answers everyone. I solved it using a sort specifier as suggested by @dpatte

8

I’ll admit I’m as confused by this as @minhna.

As you’ve described the problem, the query you initially provided will do what you want (all starred === 1 ahead of all starred === 0). Within each starred grouping, documents will be in “most recent first” order.

MyCollection.find().fetch();
(7) 0: {starred: 0, createdAt: Mon Mar 19 2018 13:31:23 GMT+0000 (GMT Standard Time), _id: "PzZdykHWGL4tRF7kK"}
    1: {starred: 0, createdAt: Mon Mar 19 2018 13:31:29 GMT+0000 (GMT Standard Time), _id: "ET4XtzdEj7h7WjxA5"}
    2: {starred: 1, createdAt: Mon Mar 19 2018 13:31:37 GMT+0000 (GMT Standard Time), _id: "n8zK9xGrXY2QAPM9T"}
    3: {starred: 1, createdAt: Mon Mar 19 2018 13:31:41 GMT+0000 (GMT Standard Time), _id: "e8BbTp9GFx6zkTNFT"}
    4: {starred: 0, createdAt: Mon Mar 19 2018 13:36:51 GMT+0000 (GMT Standard Time), _id: "uoKzw3PzKB84kLQFf"}
    5: {starred: 0, createdAt: Mon Mar 19 2018 13:36:52 GMT+0000 (GMT Standard Time), _id: "jcYPoz6XSC6XfRmbu"}
    6: {starred: 1, createdAt: Mon Mar 19 2018 13:38:00 GMT+0000 (GMT Standard Time), _id: "sx9PSE4vXaNyDz3Rv"}

MyCollection.find({},{ sort:{ starred:-1, createdAt:-1 } }).fetch();
(7) 0: {starred: 1, createdAt: Mon Mar 19 2018 13:38:00 GMT+0000 (GMT Standard Time), _id: "sx9PSE4vXaNyDz3Rv"}
    1: {starred: 1, createdAt: Mon Mar 19 2018 13:31:41 GMT+0000 (GMT Standard Time), _id: "e8BbTp9GFx6zkTNFT"}
    2: {starred: 1, createdAt: Mon Mar 19 2018 13:31:37 GMT+0000 (GMT Standard Time), _id: "n8zK9xGrXY2QAPM9T"}
    3: {starred: 0, createdAt: Mon Mar 19 2018 13:36:52 GMT+0000 (GMT Standard Time), _id: "jcYPoz6XSC6XfRmbu"}
    4: {starred: 0, createdAt: Mon Mar 19 2018 13:36:51 GMT+0000 (GMT Standard Time), _id: "uoKzw3PzKB84kLQFf"}
    5: {starred: 0, createdAt: Mon Mar 19 2018 13:31:29 GMT+0000 (GMT Standard Time), _id: "ET4XtzdEj7h7WjxA5"}
    6: {starred: 0, createdAt: Mon Mar 19 2018 13:31:23 GMT+0000 (GMT Standard Time), _id: "PzZdykHWGL4tRF7kK"}
2 Likes
9

@robfallows That is very weird because it didn’t work out for me.

I ended up doing it like this

(server)

Meteor.publish('topics', function(limit) {
        check(limit, Number);

      	return Topics.find({}, {
          limit: limit,
          sort: {starred:-1}
        });
    });

(client)

Template.indexTopics.helpers({
        topics: function () {
            var cursor = Topics.find({});
            cursor.sorter = {
              getComparator: function() {
                return function(a, b) {
                    if (a.starred) return (b.starred) ? 0 : -1;
                    if (b.starred) return 1;
                    return b.createdAt - a.createdAt;
                }
              }
            };
            return cursor;
        }
    });

As a side note, I didn’t mention it because I didn’t think it was relevant, but I’m using this for an infinite scrolling system. Nonetheless, it is working now.