I have a collection where every record has an image (thumbnail). Name of the filed is "thumbnail" and it contains this:

{

  "_id": "thumb-n9ojr7aa8",

  "size": 7099,

  "mimeType": "image/jpeg",

  "_filename": "34d1ebd4-4728-455e-8807-190a00798695",

  "_acl": {

    "creator": "54aeae56c0f223865101f894"

  },

  "_kmd": {

    "lmt": "2015-04-17T10:07:44.009Z",

    "ect": "2015-04-16T15:28:33.802Z"

  },

  "_downloadURL": "http://storage.googleapis.com/kinvey_production_da839956b9c54d749b196e68a2fb7d5b/thumb-n9ojr7aa8/34d1ebd4-4728-455e-8807-190a00798695?GoogleAccessId=558440376631@developer.gserviceaccount.com&Expires=1429270998&Signature=NItWQ4qmthOXjXNpEP73%2BHTxFAUegSzKOQlbO%2F4mIi0hMuJhiJ2AttAZFvM1bqeLGPXwhiil3VgqzZ5amZ%2Bt9LQ%2FJfaDTrh4uD1WKVqMhVmiG3o0AfIoLiOGdsB5RUAKyiFcxfItDDO3Fd8f32pYbCDTFsqG2%2BdTSCTIpuH7wZo%3D",

  "_expiresAt": "2015-04-17T11:43:18.250Z",

  "_type": "KinveyFile"

}

When I request the record via Kinvey.DataStore.find with no query parameter it returns the thumbnail object with all the data including the _downloadURL, but when I use query to limit the number of fields (e.g. query = query.fields(["_id", "name", "pies", "flows", "thumbnail"]); the thumbnail object I receive does not contain the _downloadURL any more, it only contains 

{_type: "KinveyFile", _id: "thumb-jhtk3ccoi"}.

Why? How do I get limited fields from my collection while also receiving the _downloadURL of my thumbnail?

nice workaround, thanks 

Good morning again Daniel,

Our wonderful JS developer Thomas has whipped up a query that should solve the issues that you are running into:

var query = new $kinvey.Query();
 query.equalTo('name', ‘John Doe');
 query.fields(['_id', 'thumbnail']);
 $kinvey.DataStore.find('employees', query, {
   relations: {
     thumbnail: 'files'
   }
}).then(function(response) {
   console.log(response);
});

We think that this should grab what you need.   The relations bit is what is grabbing the downloadURL for you

Please let me know if you have any other questions,