Application Quality in React

Application Quality covers the work that makes a React app look good, fail gracefully and stay fast.

What each lesson covers:

• Styling Components: Importing CSS files, className, multiple classes, inline styles, dynamic and conditional styling, and CSS Modules with scoped class names.
• Error Handling: React errors, try/catch with async code, API error handling, friendly error messages, error boundaries, fallback UI, debugging and React Developer Tools.
• Performance Optimization: How React renders, avoiding extra re-renders, memoization with React.memo, useMemo and useCallback, lazy loading, code splitting and best practices.

These lessons build on everything before them and prepare you for the capstone project.

Every page runs real React in your browser. Edit the code and see the result next to it. Each lesson ends with exercises that check what your app shows, not how your code is written.

Lessons in this section

1. Styling Components

   CSS in React: importing CSS files, className, multiple classes, inline styles, dynamic and conditional styling, and CSS Modules with scoped class names.

2. Error Handling

   React errors, try/catch with async code, API error handling, friendly error messages, error boundaries, fallback UI, debugging and React Developer Tools.

3. Performance Optimization

   Why performance matters, how React renders, avoiding extra re-renders, memoization with React.memo, useMemo and useCallback, lazy loading, code splitting and best practices.