Ember Data 1.0.0-beta.11: How to find out if async relationship is empty?

1
votes

I'm trying to update an app from Ember Data 1.0.0-beta.9 to 1.0.0-beta.11, and quite a bit seems to have changed. Specifically, I'm running into issues with finding out if a model instance does indeed have an associated model instance.

A = DS.Model.extend({
  b: belongsTo('b', { async: true }),
});

B = DS.Model.extend({
  a: belongsTo('a', { async: true }),
});

In Ember Data 1.0.0-beta.9, a.get('b') would simply return null if no associated model is found. That makes it easy to filter by computed property macros.

In Ember Data 1.0.0-beta.11, a.get('b') returns a promise, which makes it much harder to use in computed property macros. If the promise is fulfilled and the content of the promise is null, there's no associated record. But I have no idea whether it is possible to implement this check inside a Ember.computed.filter.

I have quite a few Ember.computed.filters probing quite a few Ember.isEmpty(a.get('b'))s, so I'm looking for a good way to check whether an object's async relationship is empty. Am I missing something obvious, like a built-in Ember Data api call? How would you implement such a check, if you need to filter by associated property presence/absence?

2
ember.jsember-data

2 Answers

1
votes

Well, to answer my own question, I got around this by filtering for Ember.isEmpty(a.get('b.id')), b/c I usually deal with persisted records and was able to ship around the edge cases. Sometimes it's so simple… :D

0
votes

if the related record is just created and isNew is true, checking the id property would also return null. In my case this causes unexpected results. How I managed to overcome this is by checking the content property instead. For a newly created record this will return the model class, and null if the related object is empty.