在Angular 7中，http-put请求在后端(NodeJs)发送未定义的数据

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

constructor(private http: HttpClient) { }

const url = 'http://your-backend-url/api/endpoint';
const data = { ... }; // 定义和初始化要发送的数据

this.http.put(url, data).subscribe(
  response => {
    // 处理成功响应
  },
  error => {
    // 处理错误响应
  }
);

const express = require('express');
const bodyParser = require('body-parser');

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

app.put('/api/endpoint', (req, res) => {
  const data = req.body; // 获取请求体中的数据

  // 处理数据

  res.send('Success'); // 发送成功响应
});

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