Express: call a middleware from another middleware

Completely misread your question. If you want to call requireValidToken for certain situations, you can pass along the req and res objects to the middleware function, along with an anonymous callback. How you get the middleware function largely depends on your application architecture so I’ll assume I have the requireValidToken within my context:

var requireRole = function(role) {
  return function(req, res, next){
    // Dummy tests...

    requireValidToken(req, res, function () {
      if(req.user.role == roles.admin || req.user.role == role){
        next();
      } else {
        return res.status(403)({
          success: false,
          message: "Token valid, but you don't have the right permission to access this resource :)"
        });
      }
    });
  }
};