gistfile1.js

var express = require('express'),
    reqpromise = require('request-promise');

   function register(req, res, next) {
        var user = {};
        user.username = req.body.username;
        user.password = req.body.password;
        user.firstName = req.body.firstName;
        user.lastName = req.body.lastName;
        user.email = req.body.username;

        getAdminToken(next)
            .then(registerWithTaas)
            .then(registerWithCustomerPortal)
            .then(sendResponse)
            .catch(next);

        function registerWithTaas(adminToken) {
            var url = config.taasUrl + config.register,
                options = {
                    json: {
                        'username': user.username,
                        'password': user.password,
                        'groups': [],
                        'active': true,
                        'adminToken': adminToken
                    }
                };

            return reqpromise.post(url, options).then(function (registeredUser) {
                user.uuid = registeredUser.uuid;
            });
        }

        function registerWithCustomerPortal() {
            var url = config.customerDomain + config.customerRegister,
                options = {
                    json: {
                        'uuid': user.uuid,
                        'username': user.username,
                        'email': user.email,
                        'firstName': user.firstName,
                        'lastName': user.lastName
                    }
                };

            return reqpromise.post(url, options).then(function (registeredUser) {
                return registeredUser;
            });
        }

        function sendResponse(data) {
            res.status(200).send(data);
        }
    }
    
    

Yup, tested and that works. My previous attempts were obviously filled with weak code SNAFUs.

Thanks for the push to tidy it up!