How to update a nested array in MongoDB+Node.js

Question

How to update a nested array in MongoDB+Node.js

So I have a playlist document which includes an item array. Now I want to add a vote array to the item, but I am not sure how to do this. Currently this is how I add a new item...

playlist_collection.update(
  {"PlaylistName": playlistName},
  {"$push": {items: newitem}},
  function(error, playlist){
    if( error ) callback(error);
  });

I know there are a few more posts about this so if there is a good example duplicate is fine.

Here is the object in the db

{ "PlaylistName" : "MyFirstPlaylist", 
  "_id" : ObjectId("4fe0c6570fb2321b39000001"), 
  "comments" : [ ], 
  "created_at" : ISODate("2012-06-19T18:35:03.462Z"), 
  "items" : [   
      {     "SongName" : "Test",    "Location" : "/tmp/40dd4f78466c3c7171f1eaf448e8f1d6" } 
  ] 
}

node.js
mongodb

Answer 1

I ended up using this....

PlaylistProvider.prototype.addVoteToItem = function(, itemname, vote, callback) {
  this.getCollection(function(error, collection) {
    collection.findOne({'PlaylistName':playlistName}, function (err, playlist) {
      if( err ) callback( err );
      playlist.items.forEach(function (item) {
        for (var prop in item) {
          if (prop == 'SongName'){
            if(item[prop] == itemname){
              console.log("Found "+item[prop])
              if( item.votes === undefined ) item.votes = [];
          item.votes.push(vote)
              collection.save(playlist)
              callback(null, playlist)
              break;
            } 
          }  
        }
      })
    })
  })
}