api/middleware/cors.js

function middleware(req, res, next){
  res.header('Access-Control-Allow-Origin', '*');
  res.header('Access-Control-Allow-Methods', 'GET, OPTIONS');
  res.header('Access-Control-Allow-Headers', 'X-Requested-With,content-type');
  res.header('Access-Control-Allow-Credentials', true);
  next();
}

module.exports = middleware;