如何将令牌从服务器端发送到客户端？

const express = require('express');
const jwt = require('jsonwebtoken');
const app = express();

app.use(express.json());

const SECRET_KEY = 'your_secret_key';

app.post('/login', (req, res) => {
    // 假设验证成功
    const user = { id: 1, username: 'exampleUser' };
    const token = jwt.sign(user, SECRET_KEY, { expiresIn: '1h' });
    res.json({ token });
});

app.listen(3000, () => {
    console.log('Server is running on port 3000');
});

fetch('http://localhost:3000/login', {
    method: 'POST',
    headers: {
        'Content-Type': 'application/json'
    },
    body: JSON.stringify({ username: 'exampleUser', password: 'password' })
})
.then(response => response.json())
.then(data => {
    console.log('Token:', data.token);
    // 将令牌存储在本地存储或Cookie中
    localStorage.setItem('token', data.token);
})
.catch(error => console.error('Error:', error));