MongoDB Edit an object in array if it exists - else push a new object

Question

For the following document in a collection 'users':

{
 _id: ObjectId(1234),
 name: "Joe Bloggs"
 events: [
   {
     date: 1378335600, //timestamp representing the start of day
     venues: [<venue_id>, <venue_id>, ...]
   },
   {
     date: 1378249200 //the previous day
     venues: [<venue_id>]
   }
 ]
}

Question: I would like to push a new venue_id to the venues array for a given date.

However if an event object does not exist with the corresponding date a new event object will be push to the events array with the new date and the venue pushed to the venues array.

Current solution:

Try the update with the date, if this fails, then we know the new event object needs to be created. Something like this:

Users.findOneAndUpdate({_id: 1234, "events.date": <timestap>}, 
                       { $push: {"events.$.venues" : <venue_id>} }, 
  function(err, result) {
    if(err || !result) { 
      //Issue another mongoose update to push the new event with 
      //the new date and add the venue array with the <venue_id>
    } else {
      //the update was successful as there already was a event object 
      //with the corresponding date.
    }
 });

Is there a cleaner solution to this problem?

Nilesh Rajani · Accepted Answer · 2013-09-05 16:54:38Z

1

You can perform upsert to get the desired results

Users.update({ name: "Joe Bloggs", "events.date" : 1378335600 },{ $push: {"events.venues": 1}},{ upsert: true }, function(err{...})

answered Sep 5, 2013 at 16:54

Nilesh Rajani

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1 Comment

bmullan91 Over a year ago

This doesn't solve the problem: In the case where an event doesn't exist with the correct date it will replace the events array with the object. Also - the upsert flag cannot be used with the $ positional operator.

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