React from Zero: Building Your First Component Tree

React changed how we think about interfaces by making the UI a pure function of state. The smallest unit of that idea is the component.

Thinking in components

Break a page into pieces: a layout, a header, a nav, a list, and individual items. Each piece becomes a component that receives props and returns markup. Props flow one way — down the tree.

Composition over inheritance

React favours composition. Build small, focused components and combine them, rather than building deep class hierarchies. This keeps each piece readable and testable.

A practical example

Start with a <Card> that composes a title, description, and action buttons. Reuse it wherever you need a consistent surface, and override details through props instead of copying markup.

Wrapping up

Mastering components is the foundation of everything else in React — hooks, state management, and performance. Get the composition model right and the rest follows naturally.