React component doesn't show up on Heroku but shows on local - node.js

Question

I am trying to deploy my react app on heroku but only shows index.html without all the components. The app is working fine on localhost. I made a form.js for creating server for nodemailer.
my directory looks like
src
- index.js
form.js
package.json
my package.json
{
"name": "earthly",
"version": "0.1.0",
"private": true,
"proxy": "http://localhost:3001",
"engines": {
"node": "8.11.1",
"npm": "6.2.0"
},
"dependencies": {
"axios": "^0.18.0",
"body-parser": "^1.18.3",
"concurrently": "^3.6.0",
"data.js": "^0.11.5",
"express": "^4.16.3",
"nodemailer": "^4.6.7",
"nodemon": "^1.18.3",
"npm": "^6.2.0",
"react": "^16.4.1",
"react-dom": "^16.4.1",
"react-router-dom": "^4.3.1",
"react-scripts": "1.1.4",
"react-stripe-checkout": "^2.6.3",
"react-stripe-elements": "^2.0.1",
"reactstrap": "^6.3.0"
},
"scripts": {
"start": "concurrently \"cross-env NODE_PATH=src react-
scripts start\" \"node index.js\"",
"server": "nodemon form.js",
"dev": "npm run server",
"build": "react-scripts build",
"test": "cross-env NODE_PATH=src react-scripts test --
env=jsdom",
"eject": "react-scripts eject"
},
"devDependencies": {
"cross-env": "^5.2.0"
},
form.js
app.use(express.static(__dirname + '/public'));
app.get('/', function(req, res) {
res.sendFile('index.html');
});
app.listen(process.env.PORT, '0.0.0.0', function(err) {
console.log("Started listening on %s", app.url);
});
Build log on Heroku
Node.js app detected
-----> Creating runtime environment
NPM_CONFIG_LOGLEVEL=error
NODE_VERBOSE=false
NODE_ENV=production
NODE_MODULES_CACHE=true
-----> Installing binaries
engines.node (package.json): 8.11.1
engines.npm (package.json): 6.2.0
Resolving node version 8.11.1...
Downloading and installing node 8.11.1...
Bootstrapping npm 6.2.0 (replacing 5.6.0)...
npm 6.2.0 installed
-----> Restoring cache
Loading 2 from cacheDirectories (default):
- node_modules
- bower_components (not cached - skipping)
-----> Building dependencies
Installing node modules (package.json + package-lock)
audited 21180 packages in 16.791s
found 20 moderate severity vulnerabilities
run `npm audit fix` to fix them, or `npm audit` for
details
-----> Caching build
Clearing previous node cache
Saving 2 cacheDirectories (default):
- node_modules
- bower_components (nothing to cache)
-----> Pruning devDependencies
removed 3 packages and audited 21170 packages in
14.867s
found 20 moderate severity vulnerabilities
run `npm audit fix` to fix them, or `npm audit` for
details
-----> Build succeeded!
-----> Discovering process types
Procfile declares types -> react, web
-----> Compressing...
Done: 62.6M
-----> Launching...
Released v45
https://earthly.herokuapp.com/ deployed to Heroku
I am a student and it is my first time making app with react and heroku so don't know about what to do. If someone can help it would be much appreciated! Thank you.