Populating Ember.Select from a dependent controller using EmberData lazy-loading - ember.js

Question

I have spent about 10 days on a simple problem I could have solved in about 10 minutes with Dojo. I hope I am missing something simple - I'm a noob who would like to use Ember.
I am simply trying to populate the content of an Ember.Select with data from another Controller using EmberData. Consider the case: being able to select a FoodGroup for a Raw Ingredient.
It seemed clear to use a 'needs' dependency between RawIngredientController and FoodGroupsController, and bind on the content.
This is the closest I have gotten to success and it does not look sufficient to me - I will explain.
<script type="text/x-handlebars" data-template-name="rawIngredients">
{{#each item in controller itemController="rawIngredient" }}
{{! view Ember.Select
contentBinding="controllers.foodGroups.content"
optionValuePath="content.id"
optionLabelPath="content.name"
prompt="select Food Group" }}
{{/each}}
</script>
Cook.RawIngredientController = Ember.ObjectController.extend({
isEditing: false,
needs: ['foodGroups'],
...
});
Cook.RawIngredient = DS.Model.extend({
name: DS.attr('string'),
nameKey: DS.attr('string'),
foodGroup: DS.belongsTo('Cook.FoodGroup')
});
Cook.FoodGroupsRoute = Ember.Route.extend({
setupController: function(controller) {
controller.set('content', Cook.FoodGroup.all()); // have also tried find()
}
});
Cook.FoodGroup = DS.Model.extend({
name: DS.attr('string'),
nameKey: DS.attr('string')
});
This actually renders all RawIngredients with no errors, but the Selects are empty because the FoodGroups store is empty. I can navigate to the FoodGroups screen which loads the store, come back to RawIngredients, and the selects are populated with FoodGroups.
I've seen a number of posts on this issue but none sufficiently address the issue when EmberData is involved. There are plenty of post-loaded examples, like this clever one from pangratz http://jsfiddle.net/pangratz/hcxrJ/ - but I haven't found any using EmberData to lazy-load the content.
This post is pretty close
Ember.js: Ember.Select valueBinding and lazy loading
and contains a workaround using an observer, which I couldn't get to work. I ended up binding to a binding which never invoked the actual loading of the FoodGroup data. Here's an example, maybe not the best, of one such attempt (of probably 20+):
Cook.FoodGroupsController = Ember.ArrayController.extend({
...
// NOTE: This seems redundant
values: function() {
return this.get('content');
}.property(),
...
});
Cook.RawIngredientController = Ember.ObjectController.extend({
...
// this should be the instance; also tried the object name FoodGroupsController....also tried using needs + 'controllers.foodGroups.values' in the binding
allFoodGroups: Ember.Binding.oneWay('Cook.foodGroupsController.values'), '
/*
// ... or rather ....??
allFoodGroups: function() {
this.get('foodGroupsBinding');
},
foodGroupsBinding: "Cook.foodGroupsController.values",
*/
...
});
{{view Ember.Select
contentBinding="allFoodGroups"
optionValuePath="content.id"
optionLabelPath="content.name"
prompt="select Food Group" }}
but it errors saying 'allFoodGroups' is providing a Binding not an Ember.Array. I think I am lost in a sea of swirling naming conventions. I could show my other attempts at this, but all had errors of undefined content.
Ugh. So backing up a bit... at least using my original solution and pre-loading the FoodGroups store should provide a workaround, however I cannot seem to get EmberData to go out and load the data, programmatically. I tried an init() function in the RawIngredientController like
init: function() {
var item = this.get('controllers.foodGroups.content.firstObject');
},
but I haven't found the right combination there either. And even if I do, it seems like the wrong approach because this will set up a reference for each RawIngredient rather than use a single reference from RawIngredients (or FoodGroups?) - but that seems like a different topic.
This is my attempt at a fiddle describing the problem http://jsfiddle.net/jockor/Xphhg/13/
Has anyone figured out an efficient, effective way to load and use stores defined in other controllers, using EmberData to lazy-load the associated content?

Answer 1

Your basic problem seems to be that you're not accessing the foodGroups route, so its setupController() never gets executed, thus the content of the select controller never gets set.
In your example, when adding a link to the route in question and clicking it, the route gets initialized and the bindings work.
I tried to update your JSFiddle, but it is linking to the "latest" version of ember-data from Github which has not been updated in a while (you're supposed to build it yourself until they make an official release), and it's also using an old version of Ember, so I was getting some weird errors.
So here is a version with the latest Ember and Ember-data: http://jsfiddle.net/tPsp5/
Notice what happens when you click the Countries link. I left behind some debugger; statements that may help you understand what gets invoked when.
As a design note, your "parent" controller should probably not depend on "child" controllers.