A quick way to get incremental ids for documents in MongoDB via the findAndModify feature. This snippet gets a new incremental/sequential ID. Keep in mind that this is not a good strategy when you database is horizontally distributed which is why MongoDB out of the box uses a much more complex algorithm to calculate _id. Use at your own risk. [S…

mongoGetNewId.js

var getNewId = function(db, callback) {

    var counters = db.collection('counters');
    var query = {'name': 'myCustomId'};
    var order = [['_id','asc']];
    var inc = {$inc:{'next':1}};
    var options = {new: true, upsert: true};
    counters.findAndModify(query, order, inc, options, function(err, doc) {

      if(err) {
        callback(err);
        return;
      }      

      var id = doc.next;
      callback(null, id);
    });

};