Advanced Configuration

For more complex scenarios, like allowing multiple origins, you can use a function for the origin option:

const corsOptions = {
  origin: (origin, callback) => {
    if (['http://example.com', 'http://another-example.com'].includes(origin)) {
      callback(null, true);
    } else {
      callback(new Error('Not allowed by CORS'));
    }
  },
  methods: 'GET,POST',
  allowedHeaders: 'Content-Type,Authorization',
};

app.use(cors(corsOptions));