Hi Bryan, If your "viewer" is written in Javascript, than the more general question of "How to I add Javascript to my Moodle page?" should apply here. Moodle uses requireJS to load Javascript as AMD modules. The developer documentation should explain how to define your code as an AMD module (if it isn't already), and how to include this in your page.
Moodle 3.8 onwards will support native es6 modules, but I believe the current method will continue to work.