React Must Know

This branch is the main React path.

It contains the concepts you need before building MERN frontend screens.

Topics here

• React from first principles.
• Bundlers and app setup.
• JSX and components.
• Props and component composition.
• Hooks and state.
• Data fetching and UI states.
• Routing.
• Data flow and shared state.

How to practice

For each topic:

1. Build a tiny example.
2. Change props or state and predict what re-renders.
3. Add loading, error, and empty states.
4. Explain what data belongs in parent state and what can stay local.

React interviews often test whether you can reason about UI state and component boundaries.