Controllers and Routes in Node js

Question

I wonder if it implies any difference between using only routes, or routes with controllers in the Node js, could someone give me some example of how to implement routes and controllers on Node using express js?

Answer 1

There’s a difference between using only routes, and using routes with controllers, the difference is if you need logic on the server or if you’re serving static content that doesn’t need logic.

The simplest example is using express to serve static files, no routes, no logic. Simply mapping:

app.use('/', express.static('minha-diretoria-root-do-site'))

Imagine you have two HTML files you want to send to the client. In practice you always have a controller, but in this case he does so little that we will say that it is only a route to serve files.

Example with no logic to justify a controller:

app.get('/', (req, res) => {
    res.sendFile(path.join(__dirname, '../minha-diretoria-root-do-site', 'index.html'));
});
app.get('/contacto', (req, res) => {
    res.sendFile(path.join(__dirname, '../minha-diretoria-root-do-site', 'contacto.html'));
});

Example where you need a controller, which may be in the same file as the example here, or in different files if it is extended:

app.get('/casas', (req, res) => {
    const query = 'SELECT name, price, rooms FROM houses';
    db.query(query, (err, rows) => {
        Promise.all([...rows].map(converterCambio)).then(items => {
            res.render('items', items);
        });
    });     
});

In this last example you do 2 asynchronous steps, and here the thing can complicate and become extensive, hence the need for controller. In the example I imagine that I send to the renderer, such as the ejs, or Pug to compile the page with the array I sent you.