Increment a {key: value} within an array of objects with MongoDB Mongoose driver

Question

I have a document that looks similar to this:

{
 'user_id':'{1231mjnD-32JIjn-3213}',
 'name':'John',
 'campaigns':
 [
 {
 'campaign_id':3221,
 'start_date':'12-01-2012',
 'worker_id': '00000'
 },
 {
 'campaign_id':3222,
 'start_date':'13-01-2012',
 'worker_id': '00000'
 },
 ...
 etc
 ...
 ]
}

Say I want to increment the campaign_id of element 7 in the campaigns array.
Using the dot with the mongoose driver, I thought I could do this:

camps.findOneAndUpdate({name: "John"}, {$inc: {"campaigns.7.campaign_id": 1}}, upsert: true, function(err, camp) {...etc...});

This doesn't increment the campaign_id.
Any suggestions on incrementing this?

Answer 1

You've got the right idea, but your upsert option isn't formatted correctly.

Try this:

camps.findOneAndUpdate(
 {name: "John"}, 
 {$inc: {"campaigns.7.campaign_id": 1}}, 
 {upsert: true},
 function(err, camp) {...etc...});

• user1460015: For some reason I do not understand, if I say: var update = 'campaigns.' + position + ".campaign_id" and then $inc: {update: 1} does not work (where position is an integer). But works fine if I spell it out like above: $inc: {"campaigns.7.campaign_id": 1}. Do you know why?
• JohnnyHK: Because you can't use a variable as a key name in a JavaScript immediate object. So you have to build up your update object programmatically. var update = {$inc: {}}; update.$inc['campaigns.' + position + ".campaign_id"] = 1;
• user1460015: ahh... interesting. Thanks!