Response for preflight requests are invalid - passport and react - reactjs

Question

We are trying to use passportjs for authenticating using ADFS. However, an error is thrown despite adding cors to our requests. Added both the server code and client code. The server code is also available here.
auth0/node-jsonwebtoken#59
Server - Code
'use strict';
// N.B. Encoding problems are being caused by jsonwebtoken
// auth0/node-jsonwebtoken#59
var app = require('express')(),
cookieParser = require('cookie-parser'),
jwt = require('jsonwebtoken'),
passport = require('passport'),
OAuth2Strategy = require('passport-oauth').OAuth2Strategy,
fs = require('fs');
var cors = require('cors');
var https = require('https');
console.warn('Not verifying HTTPS certificates');
https.globalAgent.options.rejectUnauthorized = false;
// Exported from ADFS
var adfsSigningPublicKey = fs.readFileSync('ADFS-Signing.cer','utf8');
var cert = convertCertificate(adfsSigningPublicKey);
function validateAccessToken(accessToken) {
var payload = null;
try {
payload = jwt.verify(accessToken, cert,{algorithms: ["HS256"], ignoreExpiration: true});
}
catch(e) {
console.warn('Dropping unverified accessToken', e);
}
return payload;
}
function convertCertificate (cert) {
//Certificate must be in this specific format or else the function won't accept it
var beginCert = "-----BEGIN CERTIFICATE-----";
var endCert = "-----END CERTIFICATE-----";
cert = cert.replace("\n", "");
cert = cert.replace(beginCert, "");
cert = cert.replace(endCert, "");
var result = beginCert;
while (cert.length > 0) {
if (cert.length > 64) {
result += "\n" + cert.substring(0, 64);
cert = cert.substring(64, cert.length);
}
else {
result += "\n" + cert;
cert = "";
}
}
if (result[result.length ] != "\n")
result += "\n";
result += endCert + "\n";
return result;
}
// Configure passport to integrate with ADFS
var strategy = new OAuth2Strategy({
authorizationURL: 'https://sso.xxx.com/adfs/oauth2/authorize',
tokenURL: 'https://sso.xxx.com/adfs/oauth2/token',
clientID: 'xxxxxxxx-xxxx-xxxx-xxxx-0cxxx4489fa', // This is just a UID I generated and registered
clientSecret: 'shhh-its-a-secret', // This is ignored but required by the OAuth2Strategy
callbackURL: 'http://localhost:3000/getAToken'
},
function(accessToken, refreshToken, profile, done) {
if (refreshToken) {
console.log('Received but ignoring refreshToken (truncated)', refreshToken.substr(0, 25));
} else {
console.log('No refreshToken received');
}
console.log("done ** " + profile);
done(null, profile);
});
strategy.authorizationParams = function(options) {
return {
resource: 'iggggggg' // An identifier corresponding to the RPT
};
};
strategy.userProfile = function(accessToken, done) {
done(null, accessToken);
};
passport.use('provider', strategy);
passport.serializeUser(function(user, done) {
done(null, user);
});
passport.deserializeUser(function(user, done) {
done(null, user);
});
// Configure express app
app.use(cookieParser());
app.use(cors());
app.use(passport.initialize());
// app.options('*', cors());
app.use(function(req, res, next) {
// res.header('Content-type', 'text/plain')
res.header('Access-Control-Allow-Credentials', true);
res.header('Access-Control-Allow-Origin', 'http://localhost:3000');
res.header('Access-Control-Allow-Methods', 'GET,POST');
//res.header('Access-Control-Allow-Headers', 'X-Requested-With, X-HTTP-Method-Override, Content-Type, Accept');
if ('OPTIONS' == req.method) {
res.send(200);
} else {
next();
}
});
app.get('/login', passport.authenticate('provider'),function(req, res) {
// Beware XSRF...
// res.json({ message: "ok", token: req.user });
});
app.get('/getAToken', passport.authenticate('provider'), function(req, res) {
// Beware XSRF...
console.log("*********************************");
res.cookie('accessToken', req.user);
res.redirect('/');
//res.json({ message: "ok", token: req.user });
});
app.get('/', function (req, res) {
console.log('default is called');
req.user = validateAccessToken(req.cookies['accessToken']);
res.send(
!req.user ? 'Log In' : 'Log Out' +
'
' + JSON.stringify(req.user, null, 2) + '
');
});
// app.get('/logout',cors(), function (req, res) {
// res.clearCookie('accessToken');
// res.redirect('/');
// });
app.listen(3000);
console.log('Express server started on port 3000');
And my client code is below.
const params = {
method: 'GET',
headers: {
"Access-Control-Allow-Origin": "*",
"Access-Control-Allow-Methods": "GET, POST",
"Access-Control-Allow-Headers": "Content-type",
"Access-Control-Allow-Credentials": true,
},
withCredentials: true
}
axios('/login', params)
.then(response => {
response.data;
})
.catch(error => {
debugger;
console.log('error');
})`
The error received is below.
Response to preflight request is invalid. Is something wrong with my cors?