js跨域怎么支持post

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

app.use((req, res, next) => {
  res.header('Access-Control-Allow-Origin', '*'); // 允许所有域，也可以指定特定域
  res.header('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS');
  res.header('Access-Control-Allow-Headers', 'Content-Type, Authorization');
  next();
});

app.post('/data', (req, res) => {
  res.json({ message: 'This is a cross-origin POST request!' });
});

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

fetch('http://example.com/data', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({ key: 'value' })
})
.then(response => response.json())
.then(data => console.log(data))
.catch(error => console.error('Error:', error));

fetch('http://example.com/data', {
  method: 'POST',
  credentials: 'include',
  headers: {
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({ key: 'value' })
});

res.header('Access-Control-Allow-Credentials', 'true');
res.header('Access-Control-Allow-Origin', 'http://yourfrontend.com'); // 不能使用通配符*