尽管在我的控制器中使用了等待，为什么我会收到 Promise Pending？

Question

我有一个存储库，我直接连接到我的模型以插入一些数据，它成功创建了数据，但是当我将控制器连接到这个存储库时，我得到一个空响应，如果我将它记录到存储库本身我得到承诺 。请在下面查看我的代码：-

Repository.js

exports.register = (request) => {
  const data = UserModel.findOne({email: request.email})
    .then(user => {
        if(user)
        {
            return {status: 400, message: 'Email Already exist'}
        } else {
            return bcrypt.genSalt(10,  (err, salt) => {
                const newUser = new UserModel({
                    username: request.username,
                    email: request.email,
                    password: request.password
                });

                return bcrypt.hash(newUser.password, salt, async (err, hash) => {
                    if(err) throw err;
                    newUser.password = hash;
                    return newUser.save()
                        .then(user => {
                            const token = jwt.sign({id: user._id}, process.env.JWT_SECRET, {
                                expiresIn: 86400 // expires in 24 hours
                            });
                            return {status: 200, message: 'Successfully Registered', auth: true, token: token, user: user}
                        })
                        .catch(err => {
                            return {status: 400, message: err}
                        })
                })
            })
        }
})

  console.log(data) // This part is return Promise <pending>
  return data;
};

Controller.js

exports.SeedRegisteration = async (req, res, next) => {
  try {
    let element = await userRepo.register({username: "Testin", email: "Testin@test.com", "password": 
 "joe" });
      return await res.status(200).json({ status: 200, data: element })
 } catch (e) {
    return res.status(400).json({ status: 400, message: e.message });
 }
};

工作正常，但不返回数据

Answer 1

这是使用 Promise 版本的 bcrypt 的 register 函数（如果您不提供回调，bcrypt 函数会返回一个 Promise

exports.register = (request) => 
    UserModel.findOne({
            email: request.email
    })
    .then(user => {
        if (user) {
            throw 'Email Already exist'
        }
    })
    .then(() => bcrypt.genSalt(10))
    .then(salt => {
        const newUser = new UserModel({
                username: request.username,
                email: request.email,
                password: request.password
            });

        return bcrypt.hash(newUser.password, salt)
        .then((hash) => {
            newUser.password = hash;
            return newUser.save();
        })
    }).then(user => {
        const token = jwt.sign({
            id: user._id
        }, process.env.JWT_SECRET, {
            expiresIn: 86400 // expires in 24 hours
        });
        return {
            status: 200,
            message: 'Successfully Registered',
            auth: true,
            token: token,
            user: user
        }
    }).catch(err => {
        return {
            status: 400,
            message: err
        }
    });

注意：有一个嵌套的 .then - 如果您在 register 中使用 async/await，则此代码可能是完全平坦的 - 但是我不准备对答案进行如此大的重写。现在代码在一个漂亮的几乎平坦的承诺链中，将整个东西转换为 async/await 样式相对简单

Answer 2

返回 promise 的 return 语句太多。请将您的代码更新为以下内容：

    exports.register = (request) => {
    return new Promise((resolve, reject) => {
        try {
            UserModel.findOne({ email: request.email })
                .then(user => {
                    if (user) {
                        return reject({ status: 400, message: 'Email Already exist' })
                    } else {
                        bcrypt.genSalt(10, (err, salt) => {
                            const newUser = new UserModel({
                                username: request.username,
                                email: request.email,
                                password: request.password
                            });

                            bcrypt.hash(newUser.password, salt, async (err, hash) => {
                                if (err) return reject(err);
                                newUser.password = hash;
                                newUser.save()
                                    .then(user => {
                                        const token = jwt.sign({ id: user._id }, process.env.JWT_SECRET, {
                                            expiresIn: 86400 // expires in 24 hours
                                        });
                                        return resolve({ status: 200, message: 'Successfully Registered', auth: true, token: token, user: user })
                                    })
                                    .catch(err => {
                                        return reject({ status: 400, message: err })
                                    })
                            })
                        })
                    }
                }).catch(err => {
                    return reject(err)
                })
        } catch (error) {
            return reject(error)
        }
    });
};