For many front end developers, including me, a jQuery plugin was their first repository on GitHub. Reading that code again, I found many bugs and I am very grateful that no one ever used it in production. At the time, I was completely confident about my code working as I intended it to, but I never stopped to think twice about why I felt that way. Since then, the most significant tool that I have picked up is unit testing and the biggest hindrance in learning how to unit test has consistently been the event loop. For example, how do I ensure that particular code paths are followed when an element is clicked, double clicked, or if the window has scrolled into a particular state.