Unable to sort MomentJS objects in mongodb

Question

I have following kind of objects stored into mongodb:

 { _id: 5319b78ba96ea4ef5c99dd55,
    name: 'Test',

     channel: 'Right one',
     showed:
      { _isAMomentObject: true,
        _i: '12.3.2014 21:45',
        _f: 'DD.MM.YYYY HH:mm',
        _l: null,
        _strict: null,
        _isUTC: false,
        _pf: [Object],
        _a: [Object],
        _d: Wed Mar 12 2014 21:45:00 GMT-0400 (EDT),
        _isValid: true,
        _lang: [Object] } },
    

I want to fetch last 30 objects in date order. I have tried sorting in this way (and also with showed._d) put it seems to sort things in alphabetic order not by date.

db.open(function(err, db) {
                        var options = {
                            'limit': 30,
                            'sort': ['showed._i','desc']
                        }

                        db.collection('programs', function(err, collection) {
                                collection.find({}, options, function(err, docs) {
                                        docs.toArray(function(err, docs) {
                                                res.json(docs);
                                        });
                                });
                        });
                });

Answer 1

For sorting in descending order, you'll need to use '-1' instead of 'desc'. This is how it's done in the shell:

db.collection.find({}).sort({'showed._i':-1}).limit(30)

Also, the field "showed._i" is stored as a string, rather than a Date. The values will need to converted to Date type for the correct results to be returned by Sorting.

Check this post for an approach to convert string to Date type