如何将base64从ionic或angular发送到nodejs服务器？

const data = 'Hello, World!';
const base64Data = btoa(data);

import { HttpClient } from '@angular/common/http';

// ...

constructor(private http: HttpClient) {}

sendBase64Data(base64Data: string) {
  const url = 'http://your-nodejs-server.com/api/upload';
  const payload = { data: base64Data };

  this.http.post(url, payload).subscribe(
    response => {
      console.log('Data sent successfully');
    },
    error => {
      console.error('Error sending data:', error);
    }
  );
}

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

app.use(express.json());

app.post('/api/upload', (req, res) => {
  const base64Data = req.body.data;
  // 处理base64数据，例如保存到文件或存储到数据库
  console.log('Received base64 data:', base64Data);
  
  res.status(200).send('Data received');
});

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