MongoDb: add element to array if not exists [duplicate]

Answer 1

I didn't test it, but you can try something like:

yourDb.find({ name: "sport", 
              videoIDs: { $in: ["34f54e34c"] } })
      .update({$addToSet: { videoIDs: "34f54e34c" }});

If you need how: MongoDb in nodeJs implementation, you can start with:

http://jsfiddle.net/1ku0z1a1/