gistfile1.txt

export function filterBy (dependentKey, propertyKey, filterPropertyName) {
  var callback;

  if (arguments.length === 2) {
    callback = function(item) {
      return get(item, propertyKey);
    };
  } else {
    callback = function(item) {
      return get(item, propertyKey) === get(this, filterPropertyName);
    };
  }

  var arrayDK = dependentKey + '.@each.' + propertyKey;
  // Ember.computed.filter
  return filter(arrayDK, callback).property(arrayDK, filterPropertyName);
}