Mongoose findOne function is not working with authentication - node.js

Question

I am working on a model here:
// user.js
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var bcrypt = require('bcrypt');
// Define collection and schema for Users
let User = new Schema(
{
firstName: String,
lastName: String,
emailaddress: String,
password: String,
},
{
collection: 'users'
}
);
// authenticate input against database documents
User.statics.authenticate = ((emailaddress, password, callback) => {
User.findOne({ emailaddress: emailaddress })
.exec(function(error, user){
if(error){
return callback(error)
} else if (!user){
console.log('User not found!');
}
bycrypt.compare(password, user.password, function(err, result){
if(result === true){
return callback(null, user);
} else {
return callback();
}
})
})
});
module.exports = mongoose.model('User', User);
As you can see on my model I put the User.statics.authenticate on my codes to do some authentication. And then on my login.js route file:
const path = require('path');
const express = require('express');
const router = express.Router();
const db = require('../../database/index');
const axios = require('axios');
const User = require('../../database/models/user');
router.get('/', (req, res) => {
console.log('hi there this is working login get');
});
router.post('/', (req, res) => {
var emailaddress = req.body.emailaddress;
var password = req.body.password;
if( emailaddress && password ){
User.authenticate(emailaddress, password, function(err, user){
if(err || !user){
console.log('Wrong email or password!');
} else {
req.session.userId = user._id;
return res.redirect('/');
}
});
} else {
console.log('both fields are required...');
}
});
module.exports = router;
I called the function and then User.authenticate function and also I created the route for root w/c is the sample that I want to protect and redirect the user after login:
router.get('/', (req, res) => {
if(! req.session.userId ){
console.log('You are not authorized to view this page!');
}
User.findById(req.session.userId)
.exect((err, user) => {
if(err){
console.log(err)
} else {
res.redirect('/');
}
})
});
Upon clicking submit on my react form it returns this error:
TypeError: User.findOne is not a function
at Function.User.statics.authenticate (/Users/mac/Documents/monkeys/database/models/user.js:35:8)
I checked the Mongoose documentation and it seems I am using the right syntax.Any idea what am I doing wrong here? Please help! Sorry super beginner here!
PS. I've already installed and set up the basic express session too.
UPDATES:
I remove the arrow function from my call and use this.model.findOne but still get the typerror findOne is not a function
// authenticate input against database documents
User.statics.authenticate = function(emailaddress, password, callback){
this.model.findOne({ emailaddress: emailaddress })
.exec(function(error, user){
if(error){
return callback(error)
} else if (!user){
console.log('User not found!');
}
bycrypt.compare(password, user.password, function(err, result){
if(result === true){
return callback(null, user);
} else {
return callback();
}
})
})
};

Answer 1

findOne is a method on your User model, not your user model instance. It provides its async results to the caller via callback:
User.findOne({field:'value'}, function(err, doc) { ... });