gistfile1.js

unselectedOptions: function() {
    var options = this.content.get('vehicleOptions');
    var filterOptions = this.get('VehicleOptions').filter(function(option) {
      if(options.contains(option)) {
        return false;
      }
      return true;
    });
    return filterOptions.sort(function(a,b){
      return a.get('name') - b.get('name');
    });
  }.property('content.vehicleOptions.lastObject').cacheable(),