Move the js to a folder as follows-> /dev/js/front/banana/controllers/gameplay.js
\IPS\Output::i()->jsFiles = array_merge(\IPS\Output::i()->jsFiles, \IPS\Output::i()->js('front_banana', 'hangman', 'front'));
Refer to the main IPS code - do a search of the files in your IDE for \IPS\Output::i()->js( and then match up what you see in that to what you see in that apps /dev/js/ folder, and things become clearer (the addition of 'controllers' and 'templates' in to the mix doesn't appear covered in documentation)