atk4\data\Join::addFields PHP Method

    public function addFields($fields = [])
    {
        foreach ($fields as $field) {
            if (is_array($field)) {
                $name = $field[0];
                unset($field[0]);
                $this->addField($name, $field);
            } else {
                $this->addField($field);
            }
        }
        return $this;
    }