Going deep with JavaScript

Going deep with JavaScript is the next step after the advanced material. It assumes you have finished Going further with JavaScript (or equivalent experience): ES modules, async patterns, DOM performance basics, browser storage, and a couple of small projects without a framework.

The intermediate tutorials taught you to write JavaScript that works well on a page. These tutorials are about what happens when the app grows: where code lives, how state flows, how to keep the main thread responsive, and how to ship something that survives a bad network or a huge data set.

We cover architecture and boundaries, state without reaching for a framework, reactive patterns you can implement yourself, Web Workers, Streams, client-side security, profiling and memory leaks, PWA basics with service workers, and patterns for larger front ends. Two mini projects tie it together: an offline-capable notes app and a performant virtualised data table.

Everything here is plain JavaScript in the browser. No React, Vue, Svelte, or TypeScript – the ideas transfer if you use those later, but these tutorials stay framework-free so you see the machinery underneath.

Work through the tutorials in order when you can. Where the intermediate series already explains something clearly, we link back rather than repeat it.