Certificates are placed in /usr/local/psa/var/certificates/.
But their names are crypted. More over, certificates will change every year.
So how to do to use them in a node appplication ?

It seems that a node application must be https and that the code must declare the certificates :

    const privateKey = fs.readFileSync('private_key.key');
    const certificate = fs.readFileSync('ssl_certificate.cer');
    const httpsServer = https.createServer({
        key: privateKey,
        cert: certificate
    }, app);

With Plesk is there an automatic way to do that ? And if the name of the certificates are cryted, how to create links ?