await not working on mongoose model .findOne({email : req.body.email})

Question

I am new to express and mongodb... I am trying to use user.findOne({email}) function returns the user with email with await keyword but the node js throws error saying

let user = await User.findOne({ email: req.body.email });
           ^^^^^

SyntaxError: await is only valid in async function

const express = require('express');
const User = require("../models/user");
const {body, validationResult} = require("express-validator");
const router = express.Router();

// Listening the request at assigned route
router.post('/', [
    // Validation array
    body("name", "Enter name").isLength({ min: 5 }),
    body("email", "Enter valid email").isEmail(),
    body("password", "password must not be less than 5").isLength({ min: 5 })

] ,

(req, res) => {

    // Errors in a single json...
    const errors = validationResult(req)

    // If there error return the error json...
    if (!errors.isEmpty()) {
        return res.status(400).json({ errors: errors.array() });
    }

    // Check if there any user with same email...
    let user = await User.findOne({ email: req.body.email });

    if (user) {
        return res.status(400).json({ error: "A user with this email already exist..."});
    }

    // Create user...
    // user = await User.create({
    //     name : req.body.name,
    //     email : req.body.email,
    //     password : req.body.password
    // })

    // res.json(user)
    res.send("Successful request...👍");
    
})

module.exports = router

Answer 1

You can use await only in async functions. You can then just write: (req, res) => { like async (req, res) => {.

The other way would be to not use async (but that'd work too), is to use a callback function: User.findOne({ email: req.body.email }).then((user)=>{ /* Your logic here */})

In general, I prefer to not mix up async/callbacks, so I stick to only use async or only use callbacks :)