As stated elsewhere, my main purpose of studying the learn-em-architecture-in-javascript code was using the code to help me deliberately backfill gaps in my JavaScript knowledge, and after learning basic dom stuff, my main stumbling block was centered around how JavaScript actually executes code, i.e. what gets run and when and why. To that end, this free version of a Front Masters course is the best resource so far for answering my questions: https://www.youtube.com/playlist?list=PLWrQZnG8l0E5hMTpzCK8WjP3nJ93jUEyk

Too, it is a single coherent resource for defining the topics of closure, scope, execution context, callbacks, and higher order functions; topics without which it will not be possible to truly understand the code. Instead of someone having to go read numerous resources, and then gather them together, and then apply them to the code, it is all in one place within a single narrative.

And here is the FrontEnd masters workshop: https://frontendmasters.com/courses/javascript-hard-parts/