UnhandledPromiseRejectionWarning：TypeError：无法读取未定义的属性“密码”

Question

这是我的登录代码。比较用户输入的密码和存储的密码时，出现未处理的承诺。

exports.login = (req, res) => {
  try {    
    const {email, password} = req.body
    console.log(req.body)

    if(!email || !password) {
      return res.status(400).render('login', {
        message: 'Please Provide an email and password'
      })
    }

    db.query('SELECT * FROM users WHERE email = ? ',{email}, async (error, results) => {
        console.log(error)
        console.log(results)
        if( !results || !(await bcrypt.compare(password, results[0].password)) ) {
          res.status(401).render('login', {
            message: 'Email or Password is Incorrect'
          })
      }
     })

  } catch (error) {
    console.log(error)
  }
}

Console.log（错误）为空。.

已更新

Answer 1

我建议您promisify db.query，以便您可以await，然后将错误正确地捕获在catch块中，并且您的代码将是扁平化。

您的错误是由试图访问results[0]属性的undefined引起的，password表示results是一个空数组。

query的第二个参数不应为Object，而应为Array，因此，将{ email }替换为[email]：

const {
    promisify
} = require('util');

const query = promisify(db.query.bind(db));

exports.login = async (req, res) => {
    try {
        const {
            email,
            password
        } = req.body;

        if (!email || !password) {
            return res.status(400).render('login', {
                message: 'Please Provide an email and password'
            });
        }

        const results = await query('SELECT * FROM users WHERE email = ? ', [email]); // problem occur due to usage of curly brackets.
            
        if (!results || !(await bcrypt.compare(password, results[0].password))) {
            res.status(401).render('login', {
                message: 'Email or Password is Incorrect'
            });
        }

    } catch (error) {
        console.log(error);
    }
}