Currently codenamed maia-yt is a userscript (and browser extension) that enhances the user's experience on YouTube.
TypeScript - Released: 04 May 2017 - 502
A proof-of-concept of using interfaces with a dependency injection system with custom transformers
TypeScript - Released: 04 Jan 2019 - 12
This is a library to userscripts (or extensions) which will enable you to inject your userscript into the page and still have access to functions like GM_setValue.
JavaScript - Released: 01 May 2014 - 9