To develop a full-stack web application using React for the frontend and Node.js/Express for the backend, follow these steps:

1. Set up the project structure

Create a new folder for your project and navigate to it in the terminal. Then, create two folders inside: one called "frontend" and another called "backend".

```
mkdir notes-app
cd notes-app
mkdir frontend backend
```

2. Set up the backend

Navigate to the "backend" folder and initialize a new Node.js project.

```
cd backend
npm init -y
```

Install the necessary dependencies:

```
npm install express mongoose cors dotenv jsonwebtoken bcryptjs
```

Create an "index.js" file that will serve as the entry point for your backend server.

```
touch index.js
```

Inside "index.js", set up a basic Express server and connect to MongoDB using Mongoose:

```javascript
const express = require('express');
const mongoose = require('mongoose');
const cors = require('cors');
require('dotenv').config();

const app = express();
app.use(express.json());
app.use(cors());

mongoose.connect(process.env.MONGODB_URI, {
  useNewUrlParser: true,
  useUnifiedTopology: true,
});

const db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', () => {
  console.log('Connected to MongoDB');
});

app.listen(5000, () => {
  console.log('Server running on port 5000');
});
```

3. Create the Note model and API routes

In the "backend" folder, create a new folder called "models" and inside it, create a file named "Note.js". Define the schema for the Note model:

```javascript
const mongoose = require('mongoose');

const noteSchema = new mongoose.Schema({
  title: { type: String, required: true },
  content: { type: String, required: true },
  user: { type: mongoose.Schema.Types.ObjectId, ref: 'User', required: true },
});

module.exports = mongoose.model('Note', noteSchema);
```

Create a new folder called "routes" and inside it, create a file named "notes.js". Define the API routes for creating, reading, updating, and deleting notes:

```javascript
const express = require('express');
const router = express.Router();
const Note = require('../models/Note');

// Add authentication middleware here

router.get('/', async (req, res) => {
  try {
    const notes = await Note.find({ user: req.user.id });
    res.json(notes);
  } catch (err) {
    res.status(500).json({ message: err.message });
  }
});

router.post('/', async (req, res) => {
  const note = new Note({
    title: req.body.title,
    content: req.body.content,
    user: req.user.id,
  });

  try {
    const newNote = await note.save();
    res.status(201).json(newNote);
  } catch (err) {
    res.status(400).json({ message: err.message });
  }
});

router.patch('/:id', getNote, async (req, res) => {
  if (req.body.title != null) {
    res.note.title = req.body.title;
  }

  if (req.body.content != null) {
    res.note.content = req.body.content;
  }

  try {
    const updatedNote = await res.note.save();
    res.json(updatedNote);
  } catch (err) {
    res.status(400).json({ message: err.message });
  }
});

router.delete('/:id', getNote, async (req, res) => {
  try {
    await res.note.remove();
    res.json({ message: 'Note deleted' });
  } catch (err) {
    res.status(500).json({ message: err.message });
  }
});

async function getNote(req, res, next) {
  let note;
  try {
    note = await Note.findById(req.params.id);
    if (note == null) {
      return res.status(404).json({ message: 'Cannot find note' });
    }
  } catch (err) {
    return res.status(500).json({ message: err.message });
  }

  res.note = note;
  next();
}

module.exports = router;
```

4. Set up authentication

Create a new folder called "auth" and inside it, create a file named "middleware.js". Implement the JWT authentication middleware:

```javascript
const jwt = require('jsonwebtoken');

function auth(req, res, next) {
  const token = req.header('x-auth-token');
  if (!token) return res.status(401).send('Access denied. No token provided.');

  try {
    const decoded = jwt.verify(token, process.env.JWT_SECRET);
    req.user = decoded;
    next();
  } catch (ex) {
    res.status(400).send('Invalid token.');
  }
}

module.exports = auth;
```

5. Set up the frontend

Navigate to the "frontend" folder and create a new React app using Create React App:

```
cd ../frontend
npx create-react-app .
```

Install necessary dependencies:

```
npm install axios react-router-dom
```

6. Build the frontend components

Create components for displaying notes, creating notes, updating notes, and deleting notes. Use Axios to make API calls to your backend server.

7. Deploy the application

Deploy the frontend to a hosting service like Netlify or Vercel, and deploy the backend to a platform like Heroku. Make sure to set up environment variables for your MongoDB connection string and JWT secret.
프론트엔드에 React를, 백엔드에 Node.js/Express를 사용하여 풀스택 웹 애플리케이션을 개발하려면 다음 단계를 따르세요.

1. 프로젝트 구조 설정

프로젝트를 위한 새 폴더를 생성하고 터미널에서 해당 폴더로 이동합니다. 그 안에 "frontend"와 "backend"라는 두 개의 폴더를 만듭니다.

```
mkdir notes-app
cd notes-app
mkdir frontend backend
```

2. 백엔드 설정

" backend" 폴더로 이동하여 새 Node.js 프로젝트를 초기화합니다.

```
cd backend
npm init -y
```

필요한 종속성을 설치합니다:

```
npm install express mongoose cors dotenv jsonwebtoken bcryptjs
```

백엔드 서버의 진입점 역할을 할 "index.js" 파일을 만듭니다.

```
touch index.js
```

"index.js" 내에서 기본 Express 서버를 설정하고 Mongoose를 사용하여 MongoDB에 연결합니다:

```javascript
const express = require('express');
const mongoose = require('mongoose');
const cors = require('cors');
require('dotenv').config();

const app = express();
app.use(express.json());
app.use(cors());

mongoose.connect(process.env.MONGODB_URI, {
  useNewUrlParser: true,
  useUnifiedTopology: true,
});

const db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', () => {
  console.log('Connected to MongoDB');
});

app.listen(5000, () => {
  console.log('Server running on port 5000');
});
```

3. 노트 모델과 API 경로 만들기

" backend" 폴더에 "models"라는 새 폴더를 만들고 그 안에 "Note.js"라는 파일을 생성합니다. 노트 모델에 대한 스키마를 정의합니다:

```javascript
const mongoose = require('mongoose');

const noteSchema = new mongoose.Schema({
  title: { type: String, required: true },
  content: { type: String, required: true },
  user: { type: mongoose.Schema.Types.ObjectId, ref: 'User', required: true },
});

module.exports = mongoose.model('Note', noteSchema);
```

"routes"라는 새 폴더를 만들고 그 안에 "notes.js"라는 파일을 만듭니다. 노트를 만들고, 읽고, 업데이트하고, 삭제하기 위한 API 경로를 정의합니다:

```javascript
const express = require('express');
const router = express.Router();
const Note = require('../models/Note');

// Add authentication middleware here

router.get('/', async (req, res) => {
  try {
    const notes = await Note.find({ user: req.user.id });
    res.json(notes);
  } catch (err) {
    res.status(500).json({ message: err.message });
  }
});

router.post('/', async (req, res) => {
  const note = new Note({
    title: req.body.title,
    content: req.body.content,
    user: req.user.id,
  });

  try {
    const newNote = await note.save();
    res.status(201).json(newNote);
  } catch (err) {
    res.status(400).json({ message: err.message });
  }
});

router.patch('/:id', getNote, async (req, res) => {
  if (req.body.title != null) {
    res.note.title = req.body.title;
  }

  if (req.body.content != null) {
    res.note.content = req.body.content;
  }

  try {
    const updatedNote = await res.note.save();
    res.json(updatedNote);
  } catch (err) {
    res.status(400).json({ message: err.message });
  }
});

router.delete('/:id', getNote, async (req, res) => {
  try {
    await res.note.remove();
    res.json({ message: 'Note deleted' });
  } catch (err) {
    res.status(500).json({ message: err.message });
  }
});

async function getNote(req, res, next) {
  let note;
  try {
    note = await Note.findById(req.params.id);
    if (note == null) {
      return res.status(404).json({ message: 'Cannot find note' });
    }
  } catch (err) {
    return res.status(500).json({ message: err.message });
  }

  res.note = note;
  next();
}

module.exports = router;
```

4. 인증 설정

 "auth"라는 새 폴더를 만들고 그 안에 "middleware.js"라는 파일을 만듭니다. JWT 인증 미들웨어를 구현합니다:

```javascript
const jwt = require('jsonwebtoken');

function auth(req, res, next) {
  const token = req.header('x-auth-token');
  if (!token) return res.status(401).send('Access denied. No token provided.');

  try {
    const decoded = jwt.verify(token, process.env.JWT_SECRET);
    req.user = decoded;
    next();
  } catch (ex) {
    res.status(400).send('Invalid token.');
  }
}

module.exports = auth;
```

5. 프론트엔드 설정

" frontend" 폴더로 이동한 후 Create React App을 사용하여 새 React 앱을 생성합니다:

```
cd ../frontend
npx create-react-app .
```

필요한 종속성을 설치합니다:

```
npm install axios react-router-dom
```

6. 프런트엔드 구성 요소 구축

노트 표시, 노트 만들기, 노트 업데이트, 노트 삭제를 위한 구성 요소를 만듭니다. Axios를 사용해 백엔드 서버에 API 호출하기

7. 애플리케이션 배포

프론트엔드는 Netlify나 Vercel 같은 호스팅 서비스에 배포하고, 백엔드는 Heroku 같은 플랫폼에 배포합니다. MongoDB 연결 문자열과 JWT 시크릿에 대한 환경 변수를 설정해야 합니다.