在使用angular 9的heroku上部署的nodejs应用程序中存在CORS错误

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

const app = express();

app.use(cors());

// 其他应用程序路由和逻辑

app.listen(3000, () => {
  console.log('应用程序已启动在端口3000');
});

{
  "origin": ["https://example.com", "https://www.example.com"]
}

const express = require('express');
const cors = require('cors');
const corsConfig = require('./cors.json');

const app = express();

app.use(cors(corsConfig));

// 其他应用程序路由和逻辑

app.listen(3000, () => {
  console.log('应用程序已启动在端口3000');
});

{
  "/api": {
    "target": "http://localhost:3000",
    "secure": false
  }
}

"serve": {
  "builder": "@angular-devkit/build-angular:dev-server",
  "options": {
    "browserTarget": "your-app:build",
    "proxyConfig": "proxy.conf.json"
  },
  "configurations": {
    "production": {
      "browserTarget": "your-app:build:production"
    }
  }
}