Express Cookie Session 'undefined' - node.js

Question

After I define a cookie in an express cookie session, I can log it to the console with ease. However, when I attempt to access this cookie in another route of my application, it returns 'undefined'.
Setting the cookie:
router.get('/callback', catchAsync(async (req, res) => {
console.log("in /callback");
if (!req.query.code) throw new Error('NoCodeProvided');
const code = req.query.code;
const creds = btoa(`${CLIENT_ID}:${CLIENT_SECRET}`);
var response = await fetch(`https://discordapp.com/api/oauth2/token?grant_type=authorization_code&code=${code}&redirect_uri=${redirect}`,
{
method: 'POST',
headers: {
Authorization: `Basic ${creds}`,
},
});
var json = await response.json();
req.session.token = json.access_token
console.log(req.session.token)
>>> RETURNS THE TOKEN CORRECTLY <<<
Attempting to access the cookie in another route:
router.get('/loggedin', catchAsync(async (req, res) => {
console.log("/loggedin");
console.log("token: " + req.session.token);
>>> RETURNS 'token: undefined' <<<

Answer 1

In the first router.get('/callback'..) the catchAsync() function is not declared globally. It just handle this specific route, and doesn't really require a name.
You should wrap this function inside a middleware or create a function which is available globally, I don't know what is the goal but here is the 2 option.
Option 1 initiate the functionality as a middleware. The behaviour is depends on where you place it!!!! Maybe in that case doesn't fully makes sense, but you can play around, but I think you will get it.
// if you put before your router initiation it is going to have effect on all of the routes
app.use(async(req, res, next) => {
if (!req.query.code) throw new Error('NoCodeProvided');
const code = req.query.code;
const creds = btoa(`${CLIENT_ID}:${CLIENT_SECRET}`);
var response = await fetch(`https://discordapp.com/api/oauth2/token?grant_type=authorization_code&code=${code}&redirect_uri=${redirect}`,
{
method: 'POST',
headers: {
Authorization: `Basic ${creds}`,
},
});
var json = await response.json();
req.session.token = json.access_token
console.log(req.session.token)
//
// and you can do whatever want to do
// but have to call next
//
next()
})
// and your router looks like
router.get('/callback', (req, res) => {
// do what have to do
})
Option 2 - declare the middleware and use where you want
// defining this middleware somewhere in the code
const catchAsync = async(req, res, next) => {
if (!req.query.code) throw new Error('NoCodeProvided');
const code = req.query.code;
const creds = btoa(`${CLIENT_ID}:${CLIENT_SECRET}`);
var response = await fetch(`https://discordapp.com/api/oauth2/token?grant_type=authorization_code&code=${code}&redirect_uri=${redirect}`,
{
method: 'POST',
headers: {
Authorization: `Basic ${creds}`,
},
});
var json = await response.json();
req.session.token = json.access_token
console.log(req.session.token)
//
// and you can do whatever want to do
// but have to call next
//
next()
}
router.get('/callback', catchAsync, (req, res) => {
// do what have to do
})
router.get('/loggedin', catchAsync, (req, res) => {
// do what have to do
})