Using underscore.js groupBy with Ember.js - ember.js

Question

Is it possible to use underscore's groupBy function with ember.js?
I have the following attempt which is obviously not working:
var activities = App.store.findMany(App.Activity, feed.mapProperty('id').uniq())
var grouped = _.groupBy(activities, function(activity){
return activity.get('dateLabel;')
});
I get the following error:
Object App.Activity has no method 'get'
The store is loaded with the correct data so findMany will not make a remote call.
The problem is that findMany returns a DS.ManyArray which is probably a lot different than what _.groupBy is looking for.

Answer 1

You could implement your own groupBy function tailored for ember-data DS-ManyArray objects and extend _ with it:
_.emberArrayGroupBy = function(emberArray, val) {
var result = {}, key, value, i, l = emberArray.get('length'),
iterator = _.isFunction(val) ? val : function(obj) { return obj.get(val); };
for (i = 0; i < l; i++) {
value = emberArray.objectAt(i);
key = iterator(value, i);
(result[key] || (result[key] = [])).push(value);
}
return result;
};
Now you can call
var grouped = _.emberArrayGroupBy(activities, function(activity) {
return activity.get('dateLabel');
});
or more simply
var grouped = _.emberArrayGroupBy(activities, 'dateLabel');
The function above is based on underscore's original groupBy() implementation, which looks very similar:
_.groupBy = function(obj, val) {
var result = {};
var iterator = _.isFunction(val) ? val : function(obj) { return obj[val]; };
each(obj, function(value, index) {
var key = iterator(value, index);
(result[key] || (result[key] = [])).push(value);
});
return result;
};

Answer 2

Try this code:
var activities = App.store.findMany(App.Activity, feed.mapProperty('id').uniq())
var grouped = _.groupBy(activities, function(activity){
return activity.get('dateLabel;')
}).bind(this);
I did not run this code to test how it works but the idea is to 'bind' outer scope into inner closure function scope.
Hope this helps to get you some ideas...