刚开始写node，感觉写出来的代码太丑了，可读性也不强。下面这段代码是一个简单的注册逻辑，用了Promise，希望大神拍砖，给一些风格或者是写法上的建议：

    register: function(req, res) {
            var sha1 = require('crypto').createHash('sha1');
            var email = req.body.email;
            var password = sha1.update(req.body.password).digest('hex');
            var connect = mysql.connect(__dirname + '/../mysql.json', 'dbname');

            var sql = 'into user(email, password) value (?, ?)';
            emailAlreadExists(email).then(function() {
                addUser(email, password)
                    .then(function(id) {
                        res.send(res.send(lib.genAjaxRet(0, 'success', {id: id})));
                    }); 
            }, function() {
                res.send(lib.genAjaxRet(10001, lib.s('EMAIL_EXISTS')))
            }); 
        }