ember.js - How can I load associated records the first time they are accessed in Ember? -

i have computed property, fetches associated record , tries print it. first time fetch record, it's null. subsequent accesses work correctly. set 'async: true', setting false doesn't change behavior.

myapp.thingscontroller = ember.arraycontroller.extend({     myproperty: function() {          var content = this.get('content');          return content.filter(function(thing) {              console.log(thing.get('title')); // since direct attribute on model, prints fine.             var associatedthing = thing.get('associatedthing'), otherthings = [];             console.log(associatedthing.get('content')); // hasmany attribute on model, , null *first* time, fine on subsequent accesses.              otherthings = associatedthing.get('content'); // doesn't work first time either.             return thing.get('title') + otherthings[0].get('name'); // or similar.          });      }.property('content.@each') // adding observers content.associatedthing.@each not seem make difference. }); 

models like:

myapp.thing = ds.model.extend({      title: ds.attr('string'),     associatedthings: ds.hasmany('associatedthing', { async: true })  });  myapp.associatedthing = ds.model.extend({      name: ds.attr('string')  }); 

obviously, cannot use promises here since need return value function, cannot use callback (since we're in computed property.) how can make work first time associated record accessed?

edit: myproperty computed property on arraycontroller, , used showing or hiding things

actually, can use promise, not in way you're thinking. hasmany relationships, ember-data returns promisearray. means returns promise resolve array. in meantime, proxy respond get requests make undefined. then, when promise resolves, observers fired. so, if have property depend on associatedthings property, will update when promise resolves. in other words, work expected:

myapp.thing = ds.model.extend({     title: ds.attr('string'),     associatedthings: ds.hasmany('associatedthing', { async: true }),     sum: function() {         var things = this.get('associatedthings');         return things.filter(function(thing) {             return shouldfilterthing(thing);         });     }.property('associatedthings.@each.size') }); 

also, please don't bugged fact doesn't happen synchronously. trying change asynchronous synchronous make code more fragile. let ember job , handle of properties , bindings you.