Question

Does MongoDB offer a find or query method to test if an item exists based on any field value? We just want check existence, not return the full contents of the item.

Answer 1

I dont believe that there is a straight way of checking the existence of the item by its value. But you could do that by just retrieving only id (with field selection)

db.your_collection.find({..criteria..}, {"_id" : 1});