Can anyone please suggest me how to get the username of currently logged in user in React component?

I am trying to make an isomorphic app where I have created React components. Also I integrated the login with node, mongoose and PassportJS. So, now that I am using jade as the templating engine how to get the username sent over the response in the React component?

This is the logged in person function :

app.get('/profile', isLoggedIn, function(req, res) {
        res.render('comment.jade', {
            user : req.user // get the user out of session and pass to template
        });
});

In comment.jade I am doing the following :

doctype html
html
head
    title= title
    link(rel='stylesheet',href='maxcdn.bootstrapcdn.com/bootstrap/3.3.6/cs…)
    script(src="cdnjs.cloudflare.com/ajax/libs/react/0.14.…")
    script(src="cdnjs.cloudflare.com/ajax/libs/react/0.14.…")
    script(src="cdnjs.cloudflare.com/ajax/libs/babel-core/…")
    script(src="maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js…")
body
    block content
        #content
        script(type="text/babel",src='/scripts/example.js')

How to get the username in scripts/example.js?