how to know if mongodb has more records to show

Question

I'm trying to make a pagination system with ranges :

$hospitals=$qb->select('subtype','price','title','date','photos','description')
                ->field('active')
                ->equals(1)
                ->limit(10)
                ->field('date')
                ->lte($lastdate)
                ->sort('_id', 'desc')
                ->getQuery()
                ->execute()
                ->toArray();

Along with this data , I want to send a 'has_more' attribute because I've developed an infinite scroll and it would be meaningless to query data when you're sure it won't return anything.
I want to know how can I get the has_more boolean from the query above.

A way would be to calculate the total number of queries and compare with the limit , but I believe there is some way smarter and easier ..

Answer 1

When I am implementing infinite scroll or pagination with mongo, I am using the following technique (I hope you will be able to adapt it to your doctrine).

If for example I have to show X elements per scroll/page. I am selecting X+1 element. Then if exactly X+1 element was selected I am selecting new X+1 element (skipping the first X). But I output always only X elements.

If you have less than X+1, I output all of them and know that there is nothing else to show.

Another approach is not to bother with all this +1 thing and only get X elements and stop right when you encounter an empty result. After this point of time, you just stop sending requests.