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# ReactJS Code Structure

This is a React.js project structure, it follows a modular, scalable, and maintainable structure.

The goal here is to serve as a collection of resources and best practices when developing React applications.
It is supposed to showcase solving most of the real-world problems of an application in a practical way and help developers write better applications.

### Project Structure

📂 **reactjs-app**\
├── 📂 **src**\
│   ├── 📂 **api**            # API call functions\
│   ├── 📂 **components**     # Reusable UI components\
│   ├── 📂 **pages**          # Page-level components (Views)\
│   ├── 📂 **context**        # Global state management (React Context)\
│   ├── 📂 **hooks**          # Custom React hooks\
│   ├── 📂 **styles**         # Global and component styles\
│   ├── 📄 **App.tsx**        # Main App component\
│   └── 📄 **index.tsx**      # Entry point (renders React app)\
├── 📂 **public**             # Static assets (index.html, images, etc.)\
├── 📄 **.env**               # Environment variables\
├── 📄 **package.json**       # Dependencies and scripts\
└── 📄 **README.md**          # Project documentation

---

### **📂`src/api - API Calls`**

**Purpose:** Centralized API communication using fetch or axios.

### **📄`src/api/messageApi.ts`**

```typescript
import axios from 'axios';

const API_BASE_URL = process.env.REACT_APP_API_BASE_URL || 'http://localhost:3000';

export const sendMessage = async (text: string, userId: string) => {
  try {
    const response = await axios.post(`${API_BASE_URL}/send`, { text, userId });
    return response.data;
  } catch (error) {
    console.error('Error sending message:', error);
    throw error;
  }
};
```

### **📂`src/components - Reusable UI Components`**

**Purpose:** Contains button, input, modal, etc. components.

### **📄`src/components/Button.tsx`**

```typescript
import React from 'react';

interface ButtonProps {
  text: string;
  onClick: () => void;
}

const Button: React.FC<ButtonProps> = ({ text, onClick }) => {
  return <button onClick={onClick} className="btn">{text}</button>;
};

export default Button;
```

### **📂`src/pages - Page Components`**

**Purpose:** Page-level components that render entire views.

### **📄`src/pages/Home.tsx`**

```typescript
import React, { useState } from 'react';
import { sendMessage } from '../api/messageApi';
import Button from '../components/Button';

const Home: React.FC = () => {
  const [message, setMessage] = useState('');
  const [userId, setUserId] = useState('');
  const [response, setResponse] = useState('');

  const handleSendMessage = async () => {
    try {
      const result = await sendMessage(message, userId);
      setResponse(result.status);
    } catch (error) {
      setResponse('Error sending message');
    }
  };

  return (
    <div className="container">
      <h1>Send Message</h1>
      <input type="text" placeholder="User ID" value={userId} onChange={(e) => setUserId(e.target.value)} />
      <input type="text" placeholder="Message" value={message} onChange={(e) => setMessage(e.target.value)} />
      <Button text="Send" onClick={handleSendMessage} />
      <p>{response}</p>
    </div>
  );
};

export default Home;
```

### **📂`src/context - Global State Management`**

**Purpose:** Manages global state using React Context API.

### **📄`src/context/MessageContext.tsx`**

```typescript
import React, { createContext, useState, ReactNode } from 'react';

interface MessageContextType {
  message: string;
  setMessage: (message: string) => void;
}

export const MessageContext = createContext<MessageContextType | undefined>(undefined);

export const MessageProvider: React.FC<{ children: ReactNode }> = ({ children }) => {
  const [message, setMessage] = useState('');

  return (
    <MessageContext.Provider value={{ message, setMessage }}>
      {children}
    </MessageContext.Provider>
  );
};
```

### **📂`src/hooks - Custom Hooks`**

**Purpose:** Encapsulates reusable logic.

### **📄`src/hooks/useMessage.ts`**

```typescript
import { useContext } from 'react';
import { MessageContext } from '../context/MessageContext';

const useMessage = () => {
  const context = useContext(MessageContext);
  if (!context) {
    throw new Error('useMessage must be used within a MessageProvider');
  }
  return context;
};

export default useMessage;
```

### **📂`src/styles - Styling`**

**Purpose:** Global styles and component-specific CSS.

### **📄`src/styles/global.css`**

```css
body {
  font-family: Arial, sans-serif;
  background-color: #f4f4f4;
  margin: 0;
  padding: 0;
}

.container {
  max-width: 500px;
  margin: auto;
  padding: 20px;
}

.btn {
  background-color: #007bff;
  color: white;
  padding: 10px;
  border: none;
  cursor: pointer;
}
```

### **📄`src/App.tsx - Main App Component`**

**Purpose:** Wraps the entire application and includes global state providers.

```typescript
import React from 'react';
import { BrowserRouter as Router, Route, Routes } from 'react-router-dom';
import Home from './pages/Home';
import { MessageProvider } from './context/MessageContext';

const App: React.FC = () => {
  return (
    <MessageProvider>
      <Router>
        <Routes>
          <Route path="/" element={<Home />} />
        </Routes>
      </Router>
    </MessageProvider>
  );
};

export default App;
```

### **📄`src/index.tsx - Application Entry Point`**

**Purpose:** Renders the React app into the DOM.

```typescript
import React from 'react';
import ReactDOM from 'react-dom/client';
import App from './App';
import './styles/global.css';

const root = ReactDOM.createRoot(document.getElementById('root') as HTMLElement);
root.render(
  <React.StrictMode>
    <App />
  </React.StrictMode>
);
```

### **📄`.env - Environment Variables`**

```
REACT_APP_API_BASE_URL=http://localhost:3000
```

---

### **Reference Websites**

* **Bulletproof React - Project Structure**: [https://github.com/alan2207/bulletproof-react/blob/master/docs/project-structure.md](https://github.com/alan2207/bulletproof-react/blob/master/docs/project-structure.md)
* **Bulletproof React - ReadMe**: [https://github.com/alan2207/bulletproof-react?tab=readme-ov-file](https://github.com/alan2207/bulletproof-react?tab=readme-ov-file)