I am currently trying to implement Oauth 2.0 using axios. I am new to axios and express so please be paitent. Below are two routes, /auth/google (all routes reside inside of /auth router) and /auth/google/callback.
when calling /auth/google using AJAX to start off the chain of events needed, I get a cors error from the var url in /auth/google. I am curious on how I would go about fixing this to ensure oAuth works?

/auth/google and /auth/google/callback (in auth.js)

const REDIRECT_URI = '<http://localhost:8080/auth/google/callback>';

// Initiates the Google Login flow

router.get('/google', (req, res) => {
    const url = `https://accounts.google.com/o/oauth2/v2/auth?client_id=${CLIENT_ID}&redirect_uri=${REDIRECT_URI}&response_type=code&scope=profile email`;
    res.redirect(url);
});


router.get('/google/callback', async (req, res) => {
    const { code } = req.query;

    try {
      // Exchange authorization code for access token
      const { data } = await axios.post('<https://oauth2.googleapis.com/token>', {
        client_id: CLIENT_ID,
        client_secret: CLIENT_SECRET,
        code,
        redirect_uri: REDIRECT_URI,
        grant_type: 'authorization_code',
      });

      const { access_token, id_token } = data;

      // Use access_token or id_token to fetch user profile
      const { data: profile } = await axios.get('<https://www.googleapis.com/oauth2/v1/userinfo>', {
        headers: { Authorization: `Bearer ${access_token}` },
      });

      // Code to handle user authentication and retrieval using the profile data
      console.log("profile:" + profile);
      console.log("data:" + data);
      res.redirect('/');
    } catch (error) {
        console.error('Error:', error);
      //console.error('Error:', error.response.data.error);
      res.redirect('/login');
    }
  });

app.js

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
var mysql = require('mysql2');
const dotenv = require('dotenv').config();
const fs = require('fs');
const https = require('https');
const session =require('express-session');
var indexRouter = require('./Routes/index');
var usersRouter = require('./Routes/users');
const crypt = require('bcryptjs');
const cors = require('cors');
const submitEventFormRouter = require('./Routes/submit-event-form');
const authRouter = require('./routes/auth');
const profileUpdateRouter = require('./Routes/profile-update');
const messagesRoutes = require('./Routes/messages'); //For messages
const apiRoutes = require('./Routes/updates');//Updates

var app = express();
//app.use(cors());

const port = process.env.PORT || 4500;

//database connections setup
var conPool = mysql.createPool({
  host: 'localhost',
  database: 'organisation_db',
});
//basic middleware to parse a new "thred" of connection to each request to run concurrently
app.use(function (req, res, next) {
  req.pool = conPool;
  next();
});

app.use(session({
  secret: '$2a$10$dmz5kZK2jXNvB4rUrclLnOzQTOum.8aA.Cg/g0LWwYfdcvMjWq3HC',
  resave: true,
  saveUninitialized: true
}));

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');

app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));

// Debugging middleware
/*
app.use(function(req, res, next) {
  console.log(req.body);
  console.log(req.session);
  next();
});*/

app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));


app.use('/', indexRouter);
app.use('/users', usersRouter);
app.use('/auth', authRouter);
app.use('/profile/update', profileUpdateRouter);
app.use('/api/messages', messagesRoutes);
app.use('/api/updates', apiRoutes);

// catch 404 and forward to error handler
app.use(function (req, res, next) {
  next(createError(404));
});

// error handler
app.use(function (err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

app.get('/login', (req, res) => {
  res.sendFile(path.join(__dirname, 'public', 'login.html'));
});


module.exports = app;

request that wont go thru

googleAuth() {
      var xhttp = new XMLHttpRequest();
      xhttp.onreadystatechange = () => {
        if (xhttp.readyState === 4) {
          if (xhttp.status === 200) {
          } else {
            console.error('Failed to query google:', xhttp.statusText);
          }
        }
      };
      xhttp.open('GET', `/auth/google`, true);
      xhttp.send();
    }