In parts 1–3 we covered various ways that we optimized the loading patterns of the critical path static resources and data queries. However there is another key area we haven’t covered yet that’s crucial to improving web application performance, particularly on low-end devices — ship less code to the user — in particular, ship less JavaScript.

Since we’re already pushing data to the client at the earliest possible time in the page load — the only faster way to get data to the client would be to not have to fetch or push any data at all.