Question

我正在努力（和新的）在Javascript中实现一个好的类模式。我在我的类函数的主体中定义我的本地变量和函数，然后将公共接口作为对象返回。

但是，当我尝试在我的一个方法中返回操作的更新结果时，我无法返回正确的'this'级别 - 它返回我的回调的内部范围，而不是操作的更新结果在我的对象上。感谢任何帮助！

例如

var u=require('./models').User();

u.findUserById('1', function(err, user) {console.log(user)});

在我的db中返回db回调对象，在下面的函数中：

function User() {
    var user_uuid, local_email, local_password;

    function generateHash(password) {
        return bcrypt.hashSync(password, bcrypt.genSaltSync(8), null);
    }

    function validPassword(password, password_compare) {
        return bcrypt.compareSync(password, password_compare);
    }

    function findUserByEmail(email, callback) {
        conn.query("SELECT * FROM users WHERE local_email=$1 LIMIT 1", [email], function (error, result) {
            //var user = this.User;
            if (!error) {
                if (result.rowCount > 0) {
                    local_email = result.rows[0].email;
                    user_uuid = result.rows[0].user_uuid;

                    //load rest of user obj
                }
            }
            callback(error, this);
        });  
    }

    function findUserById(id, callback) {
        conn.query("SELECT * FROM users WHERE user_uuid='' || $1 LIMIT 1", [id], function (error, result) {
            if (result.rowCount > 0) {
                //update
                user_uuid = result.rows[0].user_uuid;
                local_email = result.rows[0].local_email;
                local_password = result.rows[0].local_password;
                callback(null, this);
            } else {
                callback(null, this);
            }
        });
    }

    function save(callback) {
        conn.query("SELECT * FROM users WHERE user_uuid='' || $1", [user_uuid], function (error, result) {
            if (result.rowCount > 0) {
                //update
                conn.query("UPDATE users SET local_email=$1, local_password=$2 WHERE user_uuid=$3", [local_email, local_password, user_uuid], function (error, result) {
                    callback(error);
                })
            } else {
                //insert
                conn.query("INSERT users (user_uuid, local_email, local_password) VALUES ($1, $2, $3)", [require('node-uuid').v1(), local_email, local_password], function (error, result) {
                    callback(error);
                })
            }
        })
    }

    return {
        user_uuid: user_uuid,

        local: {
            email: local_email,
            password: local_password
        },
        facebook: {
            id: null,
            token: null,
            email: null,
            name: null
        },
        twitter: {
            id: null,
            token: null,
            displayName: null,
            username: null
        },
        google: {
            id: null,
            token: null,
            email: null,
            name: null
        },
        generateHash: generateHash,
        validPassword: validPassword,
        findUserByEmail: findUserByEmail,
        findUserById: findUserById,
        save: save

    }
};

Answer 1

您必须指定＆＃34;这个＆＃34;的值到外部作用域中的变量和在内部作用域中使用该变量。

课程结构没有正确回归＆＃39;这个＆＃39;

1 个答案: