Getting error on await, that await is valid only on async function when using async function

Question

I am using async function to confirm if user exists in DB with same username or email.

Thing is that I have async functions in separate files. I am importing files into route for certain endpoint.

When I am sending request to register an user after removing

await

From User.CreateNewUser and User.ValidateUserExists it goes through, but when I send same request again the same user is added to the database without validating if user exists in the DB.

Here is my route

const express = require("express");
const router = express.Router();
const asyncHandler = require('../helpers/asyncHandler');
const validate = require('validate.js');
const User = require('../controllers/user-exists-check');


//Route for creating user

router.post('/', asyncHandler((req,res) => {
    const constraints = {
        username: {
            presence: true,
            length:{minimum:4,maximum:10}
        },
        password: {
            presence: true,
            length:{minimum:6, maximum:20} 
        },
        email: {
            presence: true,
            email:true
        }}
    const username = req.body.username;
    const email = req.body.email;
    const password = req.body.password;
    const permission_id = req.body.permission_id;

    const validation = validate({username, email, password}, constraints);
    if(validation) res.status(400).json({error: validation});

    const existingUser = await User.ValidateUserExists({username, email});
    if(existingUser) {
        if(username === existingUser.username) return res.status(400).json({error:`Username ${username} is already taken`});
        if(email === existingUser.email) return res.status(400).json({error:`Email is already taken`});
    }

    const newUser = await User.CreateNewUser({username, email, password, permission_id});
    return res.status(200).json({user: newUser})

}));


module.exports = router;

this is user exists check

const {UserNameExists, EmailExists, CreateUser} = require('./user-db-check');

async function ValidateUserExists(username, email) {
    if(!username || !email ) throw new Error('Not enough args provided')
    let ValidUsername = null;
    let ValidEmail = null;

    if(username) {
        ValidUsername = await UserNameExists(username);
    }
    if(email) {
        ValidEmail = await EmailExists(email);
    }
    if(ValidUsername && ValidEmail) return ValidUsername;
    return null;
}

async function CreateNewUser(args){
    return await CreateUser(args)
}

module.exports = {
    ValidateUserExists,
    CreateNewUser
}

I am expecting for it to throw this response

if(username === existingUser.username) 
return res.status(400).json({error:`Username ${username} is already taken`});

if(email === existingUser.email) return res.status(400).json({error:`Email is already taken`});

Am I using await and async wrong way? Can someone please enlighten me

Answer 1

Your problem was that your function callback you was sending to asyncHandler( wasn't marked as async, so any functions your using inside cannot use await .

Assuming your asyncHandler is expecting a promise, doing asyncHandler(async (req,res) => { should fix this.

As a side note, looking at your code there is a fundamental logic problem you might want to think about. Doing UserNameExists / EmailExits & then CreateUser , in a multi-user environment in theory could still allow the same user & email to be stored. Most databases have something called transaction locks to prevent this happening.