Embed + Sideload Relationships for a model

Is it possible to embed one relationship and sideload another?

For instance, imagine a situation like this:

"projects": [{
  "id": "1",
  "supervisor_id": "1",
  "latest_metric": {
    "id": "3",
    "completed": "0.2"
  }
}, {
  "id": "2",
  "supervisor_id": "1",
  "latest_metric": {
    "id": "5",
    "completed": "0.5"
  }  
}],
"supervisors": [{
  "id": "1",
  "first_name": "Bob",
  "last_name": "Jones"
}]

In this case, I sideload the supervisor because Bob is the supervisor of multiple project, so I don’t want to embed his info in each project payload. However, latest_metric is a distinct model, but unique to a project and embedded.

Currently, it looks like embed: true can only be specified at the serializer level. Is that assumption correct? Should we allow a user to specify this?

[sethphillips]

I might add a +1 for a pick and choose which relationships are embedded/vs sideloaded vs just serialized Ids but this thread helped me write a serializer to fit my needs for now

[juanazam]

@samselikoff that approach does work, but there there is a minor tweak to be done, at least in my case calling Serializer.prototype.serialize.apply(this, arguments) was not doing the actual serialization on my child object (in this case latestMetric, so its attributes were not converted to snake case). This resulted in the association working, but some attributes were invalid (I took a while to figure that out, it was definitely not my best programming moment).

The tweak:

export default ApplicationSerializer.extend({
  serialize(project, request) {
    let json = Serializer.prototype.serialize.apply(this, arguments);
    let latestMetricsAttrs = Serializer.prototype.serialize.apply(this, [project.latestMetric, request]);

    json.latest_metric = latestMetricsAttrs;

    return json;
  }
});

Thanks for the help and for ember-cli-mirage. If you think it might be worth to enhance the embed option per association I can find some time to work on that, it would be a pleasure.