How to deploy Svelte frontend with Node backend to Heroku?

I've created a small test app in svelte and want to push it live to Heroku. I haven't been able to figure out how to serve it up so that Heroku. I'm new to testing and trying these things on my own. I've tried configuring the package.json but have been unsuccessful.

When I deploy to Heroku it deploys successfully but shows up this in console.

Github repo here

Package.json

{
  "name": "svelte-app",
  "version": "1.0.0",
  "main": "app.js",
  "scripts": {
    "build": "node app.js && npm run build:css && rollup -c",
    "build:css": "cd public && touch global.css && cd ../ && tailwind build src/style.css -o public/global.css",
    "dev": "rollup -c -w",
    "start": "sirv public"
  },
  "devDependencies": {
    "@rollup/plugin-commonjs": "^14.0.0",
    "@rollup/plugin-node-resolve": "^8.0.0",
    "rollup": "^2.3.4",
    "rollup-plugin-livereload": "^2.0.0",
    "rollup-plugin-svelte": "^6.0.0",
    "rollup-plugin-terser": "^7.0.0",
    "svelte": "^3.0.0"
  },
  "dependencies": {
    "axios": "^0.20.0",
    "bcryptjs": "^2.4.3",
    "body-parser": "^1.19.0",
    "cookie-parser": "^1.4.5",
    "cookie-session": "^1.4.0",
    "cors": "^2.8.5",
    "dotenv": "^8.2.0",
    "express": "^4.17.1",
    "express-session": "^1.17.1",
    "mongoose": "^5.10.5",
    "passport": "^0.4.1",
    "passport-local": "^1.0.0",
    "sirv-cli": "^1.0.0",
    "tailwindcss": "^1.8.10"
  }
}

app.js

const dotenv = require("dotenv");
dotenv.config();
const mongoose = require("mongoose");
const express = require("express");
const cors = require("cors");
const passport = require("passport");
const cookieParser = require("cookie-parser");
const bcrypt = require("bcryptjs");
const session = require("express-session");
const bodyParser = require("body-parser");
const app = express();
const path = require("path");
const { URI } = process.env;
const User = require("./user");

//middleware
app.use(bodyParser.json());
app.use(
  bodyParser.urlencoded({
    extended: true,
  })
);
app.use(
  cors({
    origin: "http://localhost:5000", // <-- location of the react app were connecting to
    credentials: true,
  })
);
app.use(
  session({
    secret: "secretcode", // <-- here we are defining the cookie name to be stored in the users browser
    resave: true,
    saveUninitialized: true,
  })
);
app.use(cookieParser("secretcode"));
app.use(passport.initialize());
app.use(passport.session());
require("./passportConfig")(passport); // defining passport and passing in the passport library

//db
mongoose.connect(URI, {
  useNewUrlParser: true,
  useUnifiedTopology: true,
  useFindAndModify: false,
});
mongoose.connection.on("connected", () => {
  console.log("Mongoose Database is Connected");
});

app.post("/login", (req, res, next) => {
  //check to see if user exists
  passport.authenticate("local", (err, user, info) => {
    console.log(user);
    if (err) throw err;
    if (!user) res.json({ message: "User does not exist" });
    else {
      req.logIn(user, (err) => {
        if (err) throw err;
        res.json({ message: "User exists" });
      });
    }
  })(req, res, next);
});
app.post("/create", async (req, res) => {
  //check to see if user exists
  const { username, password } = req.body;

  try {
    const data = await User.findOne({ username });
    if (!data) {
      const hashedPassword = await bcrypt.hash(password, 10);

      const newUser = new User({
        username,
        password: hashedPassword,
      });
      await newUser.save();
      res.json({ message: "Client created" });
    } else {
      res.json({ message: "Client already exists" });
    }
  } catch (err) {
    res.json({ message: err });
  }
});
app.get("/user", (req, res) => {
  console.log("getting user...");
  res.json({ message: req.user }); // The req.user stores the entire user that has been authenticated inside of it.
});
app.get("/logout", (req, res, next) => {
  req.logOut();
  res.json({ message: "User logged out" });
});
app.use(express.static("public"));
app.get("*", (req, res) => {
  res.sendFile(path.resolve(__dirname, "public", "index.html"));
});
app.listen(5001, () => {
  console.log("App's running on port 5001");
});

from How to deploy Svelte frontend with Node backend to Heroku?