Help needed: support null values of referenced fields

[rturk]

Need help with null values when using reference fields.

I have a NewsFeed schema that contains a Product, or a Post, or a Video. Defined as follows:

NewsFeed = new mongoose.Schema({
  date: { type: Date, required: true, default: Date.now },
  product: { type: ObjectId, ref: 'Product', required: false},
  post: { type: ObjectId, ref: 'Post', required: false },
  video: { type: ObjectId, ref: 'Post', required: false }, 
});

This means that aNewsFeed document contains a date and one element (one of product, post or video).

Ideally I what to use the GraphQL query bellow and fetch my newsfeed ordered by date and containing the applicable newsfeed element with the other elements absent or null.

query{
  viewer{
    homenewsfeeds(first:5,orderBy:DATE_DESC){
      count,
      edges{
        node{
          date,
          product {
            id,
            name
          },
          post{
            id,
            title,
            author {
              id,
              name
            }
          }
          video{
            id,
            title,
            duration,
          }
        }
      }
    }
  }
}

However I get the following error:

"statusCode": 400,
  "error": "Bad Request",
  "message": "Cannot read property 'toString' of null\nCannot read property 'toString' of null\nCannot read property 'toString' of null\nCannot read property 'toString' of null\nCannot read property 'toString' of null" 

My understating is that GraphQl is trying to load the referenced object even if is not in the current element.

I've already attempted to re-create the newsfeed forcing the elements to be required defaulting to null, with no success. I'm getting the same error

NewsFeed = new mongoose.Schema({
  date: { type: Date, required: true, default: Date.now },
  product: { type: ObjectId, ref: 'Product', required: true, default: null},
  post: { type: ObjectId, ref: 'Post', required: true, default: null},
  video: { type: ObjectId, ref: 'Post', required: true, default: null }, 
});

Another option would be refactor the NewsFeed as described bellow. However this will defeat the purpose of simpler GraphQL queries.

NewsFeed = new mongoose.Schema({
  date: { type: Date, required: true, default: Date.now },
  target: { type: ObjectId},
  type: { type: String, enum: ['Post','Product','Video']},
});

Comments? This is a limitation of GraphQL or current Mongoose-GraphQl implementation?

[rturk]

@sibeliusseraphini

[rturk]

I'll test this again latter this week using latest releases..

[rturk]

With #100 my use case described above works