You know HTML, CSS and enough JavaScript to be dangerous. Twelve lessons later you will have built a working app and understand why every piece of it is there.
Beginner · 12 lessons · ~2 hours · Free · No sign-up
The problem React actually solves - and the same small interface built twice, once by hand and once by describing the result.
One command, and then a tour of every file it generated - what each one is for and which ones you will actually touch.
A component is a function that returns markup. JSX is how you write that markup, and it has about five rules worth learning up front.
Components take arguments like any other function. Props are those arguments, they only travel one way, and the component cannot change them.
Turning an array into markup with map, and the one prop React asks for in return - plus why reaching for the array index will eventually bite you.
Four ways to render something only sometimes, when to use each, and the one that quietly puts a zero on your page.
The pivot. Why changing a plain variable does nothing, what useState changes about that, and how to update state from its own previous value.
Letting React own what is in the box: one state object for a whole form, immutable updates, and submitting without reloading the page.
Two components need the same value. The answer is almost never to give them one each - it is to move it up to the nearest thing they have in common.
Effects are for synchronising with something outside React, not for running code on mount. Loading a list from an API, cleaning up after it, and the many cases where you do not need an effect at all.
The capstone. Take a mock-up, break it into components, build it static, find the smallest possible state, decide where it lives, and wire it up.
An honest map of everything this course left out - what to learn next, what can wait, and what you can safely ignore for another year.