Express JS with Webpack giving cannot find module error - node.js

Question

Hi I am new with frontend technologies so I have a question around webpack and express js. I am building an application using react , webpack , node and express js. The app.js looks like the following
app.js
const express = require('express');
const app = express();
var path = require('path');
app.use(express.static(__dirname + '/'));
app.get('/', (req, res) => { // new
res.sendFile(__dirname + "/index.html");
});
app.listen(3000, () => console.log('listening on port 3000'));
package.json looks like following
"version": "1.0.0",
"main": "app.js",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 0",
"build": "webpack --mode production",
"start": "nohup webpack-dev-server --mode development --open &",
"prepublishOnly": "cp -r configuration/* build/"
},
"repository": {
"type": "git",
"url": "ssh://git.amazon.com/pkg/SPSWebApplication"
},
"keywords": [],
"author": "",
"license": "ISC",
"devDependencies": {
"#babel/core": "^7.3.4",
"#babel/preset-env": "^7.3.4",
"#babel/preset-react": "^7.0.0",
"babel-loader": "^8.0.5",
"express": "^4.16.4",
"html-loader": "^0.5.5",
"html-webpack-plugin": "^3.2.0",
"react-dom": "^16.8.4",
"webpack": "^4.29.6",
"webpack-cli": "^3.3.0",
"webpack-dev-middleware": "^3.6.1",
"webpack-dev-server": "^3.2.1"
},
"dependencies": {
"#stencil-react/core": "*",
"#stencil-react/theme-default": "*",
"webpack": "^4.29.6",
"webpack-cli": "^3.3.0",
"react": "^16.8.4",
"webpack-dev-server": "^3.2.1",
"html-webpack-plugin": "^3.2.0"
},
"description": ""
}
webpack.config.js
const HtmlWebPackPlugin = require("html-webpack-plugin");
module.exports = {
module: {
rules: [
{
test: /\.(js|jsx)$/,
exclude: /node_modules/,
use: {
loader: "babel-loader"
}
},
{
test: /\.html$/,
use: [
{
loader: "html-loader",
options: { minimize: true }
}
]
}
]
},
resolve: { // this allows to import 'Foo.jsx'
extensions: ['.jsx', '.js', '.json']
},
plugins: [
new HtmlWebPackPlugin({
template: "./src/index.html",
filename: "./index.html"
})
]
};
when i build the code in the build folder it creates dist/app.js,main.js,index.html whenever i try to run app.js it says
Error: Cannot find module 'express'
at Function.Module._resolveFilename (internal/modules/cjs/loader.js:649:15)
at Function.Module._load (internal/modules/cjs/loader.js:575:25)
at Module.require (internal/modules/cjs/loader.js:705:19)
at require (internal/modules/cjs/helpers.js:14:16)
I want to run my application in production environment through dist/app.js but when I do "node app.js" it gives me this dependency issue I am assuming webpack should pull the express dependency in dist/* folder in a minified form which i am assuming it is not doing. Can you please if I am missing anything and my understanding is correct or not?