Enable Access-Control-Allow-Origin for multiple domains in Node.js [duplicate]

Answer 1

Here's a simple middleware function to serve up the correct CORS header from a whitelist. Setting this near the top of your express app will allow all your routes to set the proper header from the whitelist before serving up content.

app.use(function(req, res, next){
  var whitelist = ['localhost:4000', 'localhost:3000', 'anydomain.com']
  var host = req.get('host');

  whitelist.forEach(function(val, key){
    if (host.indexOf(val) > -1){
      res.setHeader('Access-Control-Allow-Origin', host);
    }
  })

  next();
});