Express get sub-domain name

Question

is there a way to use the express router to get the variable of the subdomain.

Lets say I have foo.example.com how can I get an output of foo.

Thanks

Answer 1

In Express 4.x you can use req.subdomains property.

// Host: "tobi.ferrets.example.com"
req.subdomains
// => ["ferrets", "tobi"]

ref.: https://expressjs.com/en/4x/api.html#req.subdomains

Answer 2

Express 4.x comes req.subdomains but if you are using older version or want to play your own code then can be used other framework as well then you may like

var app = express();

app.use(function(req, res, next) {
    var host = req.get('host');
    console.log(getSubdomain(host));
    console.log(getSubdomainList(host));
    next();
})

function getSubdomain(host) {
    var subdomain = host ? host.substring(0, host.lastIndexOf('.')) : null;
    return subdomain;
}

function getSubdomainList(host) {
    var subdomainList = host ? host.split('.') : null;
    if(subdomainList)
        subdomainList.splice(-1, 1);
    return subdomainList;
}