javascript - node.js 使用 mongoose 链接多个异步函数

Question

我有一个看起来像这样的函数，至少现在它可以工作。

exports.changePassword = (req, res) => {
  const { token, password, confirmPassword } = req.body

  User.findOne({resetPasswordToken: token}, (err, user)=>{
    if(!user){
      return res.status(400).send({
        msg: 'Invalid token or token has been used!'
      })
    }

    const hash_password = bcrypt.hashSync(password, 10)
    User.findOneAndUpdate({_id: user._id}, 
      {hash_password}, 
      (err, result)=>{

        if(err){
          return res.status(400).send({
            msg: err
          })
        }

        User.findOneAndUpdate({_id: user._id},
          {resetPasswordToken: ''},
          (err, result)=>{
            if(err){
              return res.status(400).send({
                msg: err
              })
            }

            res.status(200).json({
              status: 1,
              data: 'Your password has been changed.'
            })
          }
        )
      })
  })
}

我只是觉得写这段代码很糟糕，因为我认为它有几个问题:

1. 回调 hell
2. 错误处理代码重复

对于第一个问题，也许我可以使用完成参数？并做一些链接？有时我怀疑我是否需要处理每一个错误回调。您将如何重写上面的函数以使其变得更加优雅？

Answer 1

您可以将 Promise 与 Mongoose 结合使用，这将有助于解决回调 hell 问题:

exports.changePassword = (req, res) => {
  const { token, password, confirmPassword } = req.body

  User.findOne({resetPasswordToken: token}).then((user)=>{
    // do stuff with user here 

    const hash_password = bcrypt.hashSync(password, 10)
    // Now chain the next promise by returning it
    return User.findOneAndUpdate({_id: user._id}, {hash_password});
  }).then((result)=>{
    // Now you have the result from the next promise, carry on...
    res.status(200).json({
      status: 1,
      data: 'Your password has been changed.'
    })
  }).catch(err => {
    // Handle any errors caught along the way
  });
}

由于这些都是 promise ，因此您实际上可以使用 ES6 async/await 语法使其变得更加简洁:

// Note this now has the async keyword to make it an async function
exports.changePassword = async (req, res) => {
  const { token, password, confirmPassword } = req.body

  try {
    // Here is the await keyword
    const user = await User.findOne({resetPasswordToken: token});

    // do stuff with user here 

    const hash_password = bcrypt.hashSync(password, 10)

    // Now the next promise can also be awaited
    const result = await User.findOneAndUpdate({_id: user._id}, {hash_password});

    // Finally send the status
    res.status(200).json({
      status: 1,
      data: 'Your password has been changed.'
    });
  } catch (err) {
    // Any promise rejections along the way will be caught here
  });
}