express 設置允許跨域訪問

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

//設置允許跨域訪問該服務.
app.all('*', function (req, res, next) {
  res.header('Access-Control-Allow-Origin', '*');
  //Access-Control-Allow-Headers ,可根據瀏覽器的F12查看,把對應的粘貼在這裏就行
  res.header('Access-Control-Allow-Headers', 'Content-Type');
  res.header('Access-Control-Allow-Methods', '*');
  res.header('Content-Type', 'application/json;charset=utf-8');
  next();
});

app.get('/hello', function (req, res) {
  res.json({})
});

const server = app.listen(8082, function () {
  console.log('Express app server listening on port %d', server.address().port);
});