How do I replace front-end views with JSONs in Codeigniter 3?

What about something like https://www.codeigniter.com/user_guide/l...ntent_type

Instead of loading any view at all, each controller method would build its "view data" as $data, and then
$this->output->set_content_type('application/json')->set_output(json_encode($data));

How would that code look exactly, in the context of my Posts controller? For the index() method, for instance.