给出“无法读取未定义的属性'密码'”而不是处理错误

Question

I'm trying to build a user login system using express js and dynamodb, but the issue is whenever I'm trying to login a user using correct email or password, it works fine, but if I'm using any wrong email, it's not able to handle the error. It's giving me some error like cannot find password of undefined. Can someone please tell me how to handle with this error and why this error? I tried some stackoverflow question similar to mine, but that actually does not solve the problem. Thanks in advance.

This is my whole userLogin file:

 const AWS = require("aws-sdk"); const express = require("express"); const bcrypt = require("bcrypt"); const jwt = require("jsonwebtoken"); require("dotenv").config(); AWS.config.update({ region: "us-east-2" }); const docClient = new AWS.DynamoDB.DocumentClient(); const router = express.Router(); router.post("/login", (req, res, next) => { user_type = "employee"; const email = req.body.email; docClient.get( { TableName: "users", Key: { user_type, email, }, }, (err, data) => { if (err) { res.send("Invalid username or password"); } else { if (data && bcrypt.compareSync(req.body.password, data.Item.password)) { const token = jwt.sign( { email: data.Item.email, }, process.env.SECRET, { expiresIn: "1d" } ); res.status(200).send({ user: data.Item.email, token: token }); next(); } else { res.status(400).send("Password is wrong"); } } } ); }); module.exports = router;

And this is the error I'm getting:

 I:\somePath\node_modules\aws-sdk\lib\request.js:31 throw err; ^ Error [TypeError]: Cannot read property 'password' of undefined

Answer 1

You need to add something to catch when data doesn't return valid data. If you could post what the data object looks like, that would help.

(err, data) => {
  if (err) {
    res.send("Invalid username or password");
  } else {
    // Add data.Item check
    if (data && data.Item && bcrypt.compareSync(req.body.password, data.Item.password)) {
      const token = jwt.sign({
          email: data.Item.email,
        },
        process.env.SECRET, {
          expiresIn: "1d"
        }
      );
      res.status(200).send({
        user: data.Item.email,
        token: token
      });
      next();
    } else {
      res.status(400).send("Password is wrong");
    }
  }
}