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Welcome to the React collection of 30 Seconds of Code. This collection contains practical, ready-to-use function components and custom hooks designed for React 18.

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What You’ll Find Here

This collection is organized into three main categories:

Hooks

Custom React hooks for state management, side effects, and browser APIs

Components

Reusable UI components for common patterns and interactions

Testing

Testing patterns and examples for React components

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Key Features

All examples use modern React patterns including:
  • Function components with hooks
  • Declarative state management
  • Effect cleanup and dependency management
  • Custom hook composition
Each snippet is designed to be:
  • Copy-paste ready for your projects
  • Well-documented with explanations
  • Tested and validated
  • Following React best practices
Every snippet includes:
  • Complete implementation code
  • Usage examples
  • Edge case handling
  • Performance considerations

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React 18 Focus

This collection specifically targets React 18, taking advantage of:
  • Concurrent rendering features
  • Automatic batching
  • Modern hooks API
  • Updated effect behavior

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Quick Start

Here’s a simple example of a custom hook from this collection: 
const useToggle = (initialState = false) => {
  const [state, setState] = React.useState(initialState);
  const toggle = React.useCallback(() => setState(prev => !prev), []);
  return [state, toggle];
};

// Usage
const App = () => {
  const [isOpen, toggleOpen] = useToggle(false);
  return <button onClick={toggleOpen}>{isOpen ? 'Close' : 'Open'}</button>;
};
1

Explore Hooks

Start with the Hooks Overview to discover custom hooks for managing state, effects, and browser APIs.
2

Browse Components

Check out the Components Overview for ready-to-use UI components.
3

Learn Testing

Visit the Testing Overview to learn how to test React components effectively.

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Categories at a Glance

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Custom Hooks

  • Effect Hooks: useInterval, useTimeout, useEffectOnce
  • Event Hooks: useClickOutside, useClickInside
  • Network Hooks: useFetch
  • Observer Hooks: useMutationObserver, useIntersectionObserver
  • Lifecycle Hooks: useComponentDidMount, useComponentDidUpdate

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UI Components

  • Interactive: Toggle, Star Rating, Modal
  • Data Display: DataTable, TreeView, DataList
  • Feedback: Tooltip, Alert, Modal Dialog

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Testing Patterns

  • Asynchronous component testing
  • Redux connected components
  • Portal testing
  • Event simulation
All code examples in this collection use modern JavaScript syntax and assume you have a React 18 environment set up.

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