All chapters

14 chapters · updated 14 August 2026

The guide runs in order from the idea behind React through to writing your own hooks. If you are new, start at chapter 01.

What React is, the problem it solves, and the mental model that makes the rest of the guide click.

Two ways to run React: a single HTML file for experiments, and a real toolchain for actual projects.

The syntax that lets you write markup inside JavaScript, and the handful of rules that differ from HTML.

The unit React is built from: a function that returns markup, composed into a tree.

How data flows from a parent component into a child, and why it only flows that way.

Memory that survives between renders, and the rules for changing it correctly.

Responding to clicks, keys, and input in JSX, and the differences from plain DOM listeners.

Showing different output for different data, using ordinary JavaScript rather than special syntax.

Turning arrays into elements with map, and why every item needs a stable key.

Controlled inputs, multiple fields, validation, and submitting.

What hooks are, the rules that govern them, and which ones you will actually reach for.

Running code outside the render — subscriptions, timers, and data fetching — and cleaning up after it.

Sharing values across a whole tree without threading props through every level.

Reaching the DOM directly, keeping values between renders, and packaging logic for reuse.