Call a function inside async function at a js class

Question

Hi I'm new at javascript programming.

I have a node express project, I'm trying to create a login method inside my AuthenticationController class.

My login method is like this right now:

const User = require('../models/User')

class AuthenticationController {

  async login(req, res) {
    const { email, password } = req.body
    console.log('step 1')
    var hashPassword = await userPassword(email)
    console.log(hashPassword)
    console.log('step 2')
    return res.status(200).json({ 'msg': 'Log in OK!' })

  }

  userPassword(email) {
    User.findOne({ email: email }).exec(function(err, user) {
      if (err) return err
      else return user.password
    })
  }
}

But I got an error saying that userPassword is undefined, I couldn't figure out why. So my doubts are: why this is happening, and how to do it correctly ?

I also checked out this questions, but they didn't helped me:

• How to call an async function
• Async function inseide a class

The error message at my console:

(node:28968) UnhandledPromiseRejectionWarning: ReferenceError: userPassword is not defined ...

(node:28968) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)

(node:28968) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

Answer 1

login doesn't refer to userPassword method but to the function of the same name which doesn't exist.

Promises are supposed to be be chained and they aren't. userPassword is expected to return a promise but it uses obsolete Mongoose callback API.

That UnhandledPromiseRejectionWarning is shown means that errors weren't correctly handled in login while they should. As explained in this answer, Express don't support promises so errors should be handled by a developer.

It should be:

  async login(req, res) {
      try {
        const { email, password } = req.body
        var hashPassword = await this.userPassword(email)
        return res.status(200).json({ 'msg': 'Log in OK!' })
      } catch (err) {
        // handle error
      }
  }

  async userPassword(email) {
    const { password } = await User.findOne({ email: email });
    return password;
  }