mozilla's client-sessions aren't being saved

For some reason, the sessions aren't being saved in between calls. I know there are other questions like this, but their answers don't help my problem.

server code:

var express = require('express');
var app = express();
var http = require('http').Server(app);
// var io = require('socket.io')(http);
var { db } = require("./db.js");
const cors = require('cors');
var bcrypt = require("bcrypt");
var session = require('client-sessions');

var bodyParser = require('body-parser');
app.use(bodyParser.json()); // support json encoded bodies
app.use(bodyParser.urlencoded({ extended: true })); // support encoded bodies

app.use(cors({
    origin: "http://localhost:8080",
    credentials: true
}));

var salt1 = bcrypt.genSaltSync();
var salt2 = bcrypt.genSaltSync();
var secret = bcrypt.hashSync(salt1 + salt2, 10);
app.use(session({
    // activeDuration: toTime("days", 7),
    cookieName: 'session',
    // duration: toTime("days", 7),
    secret, // set this to a long random string!,
}));

http.listen(process.argv[2] || 8081);

app.get("/", function (req, res) {
    console.log(req.session)
    let { email, firstname, lastname, id } = req.session
    req.session.username = "tester"
    if (req.session.id) {
        res.send({
            email,
            firstname,
            id,
            lastname,
            success: true
        })
    }
    else {
        res.send({
            session: req.session,
            success: false
        })
    }
})

I know that the session exists because I can all it and assign it. It just doesn't save the data when I call / path again. It only displays {}