Middleware to prevent cors errors (Express.js)

cors.js

// middleware that ensures that cors errors are prevented
app.use((req, res, next) => { 
    res.header('Access-Control-Allow-Origin', '*'); // allow the access of the api, to all clients/websites asking
    res.header('Access-Control-Allow-Headers', '*'); // which kind of header we want to accept 
    if(req.method === 'OPTIONS') {
        res.header('Access-Control-Allow-Methods', 'PUT, POST, PATCH, DELETE');
        return res.status(200).json({});
    }
    next();
})