Ember Data - async Record.get().then gives still-isLoading object!

Ember Data
1

I’ve encountered an odd problem with Ember Data (3.12.6 - latest LTS).

Specifically, I have this type of thing:

    somethingObserver: observer('record.SomeRelationship', function() {
        record.get('SomeRelationship').then(val => {
            console.log(val.get('isLoading'),val.get('SomeProperty');
        });
    })

(and yes, there might be better ways of doing this without the observer, but I don’t think that affects the validity of the example).

The console.log here will output:

true undefined

which seems like it should be impossible?

Even more weird, if I expand it to do:

    somethingObserver: observer('record.SomeRelationship', function() {
        record.get('SomeRelationship').then(val => {
            console.log(val.get('isLoading'),val.get('SomeProperty');
            const rightVal = store.peekRecord(val.constructor.modelName,val.id);
            console.log(rightVal.get('isLoading'),rightVal.get('SomeProperty');
        });
    })

then I get output of:

true undefined
false TheCorrectValue

In other words, the object returned from the then is not finished loading, but if I do a peekRecord into the store for the exact same object, it gives me the proper fully defined object!

I’ve verified that the over-the-network traffic looks good, and everything is coming back successfully.

The only thing that is interesting, is if I do an Ember.guidFor on both the object returned by the then and the object coming from peekRecord, I get:

  • The object from the then: ember1234
  • The object from the peekRecord: st4567

I’m not sure if the difference in prefix on the guidFor tells us anything interesting?

Would anyone be able to point me in the right direction for debugging this? (I’m fine with stepping into the Ember Data code, but would appreciate some insight as to where one could look.)

Thanks in advance!

2

OK, I’ve finally solved this.

Basically, the problem was a polymorphic model, and when the backend returned a model, the relationships on that model were marked with a type of the abstract superclass, NOT the concrete class that it should have been.

So the relationship data looked something like:

"data": {
    "type": "abstract-thingy",
    "id": 123
}

instead of the proper:

"data": {
    "type": "thingy-type-a",
    "id": 123
}

Hopefully this can help someone else if they encounter the same insanely-difficult-to-track-down problem.

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