YII ERROR - Trying to get property 'alias' of non-object

Question

I'm new in Yii development and I am getting an error followed by Trying to get property of non-object

Do somebody can help me please ?

1. in /var/www/vhosts/sitename/httpdocs/application/models/Profile.php at line 498

   * @param $category
     * @return ProfileField|array|mixed
     */
    protected function getProfileFields($category)
   {
        if (!isset($this->_profileFields)) {
            $data = [];
            $fields = ProfileField::find()->joinWith('category')->visible()->sorted()->all();
            foreach ($fields as $field) {
                $data[$field->'category'->alias][] = $field;
            }
            $this->_profileFields = $data;
        }
 
        return isset($this->_profileFields[$category]) ? $this->_profileFields[$category] : [];
    }

Answer 1

Change your code to:

foreach ($fields as $field) {
    if ($field->category) {
        $data[$field->category->alias][] = $field;
    }
}