Mathias Bynens and Benedikt Meurer:
As a JavaScript developer, having a deeper understanding of how JavaScript engines work helps you reason about the performance characteristics of your code.
I especially like the part where they take a look into an JS engine’s Object Model:
How do JavaScript engines implement the JavaScript object model, and which tricks do they use to speed up accessing properties on JavaScript objects? As it turns out, all major engines implement this very similarly.
(knowledge of the aforementioned Property Descriptors will come in handy ;))
The contents of the article have also been touched upon in this duo-talk they gave: