Dockerizing react app with webpack, connection issues

I'm lately trying to dockerize my react app to learn docker. I'm using weback for managing this project. Now here is the thing, after I run dev script npm run dev, server gets on, but I'm not able to connect to it either on host (posting container on 3000:3000) and inside container for any-given ports that came up to my mind (like 8000, 8080, 3000, 5000). It just seems to me like the port connection is not set up properly. Reading some webpack docs did not give me any clue.

The questions are: best way to define server scripts to run ? My way of doing it is:

"scripts": {
    "dev": "webpack --mode development --watch",
    "build": "webpack --mode production"
  },

Is there any default-like port that webpack sets its connection to (maybe a way to change it)?

What I did establish, is that for 90% it's my webpack config. After dockerizing react app with create-react-app I did have successfull start.

My webpack.config.js :

const path = require("path");
const webpack = require("webpack");

module.exports = {
  entry: { index: path.resolve(__dirname, "src", "index.js") }, //"./src/index.js",
  output: {
    path: path.resolve(__dirname, "./static/frontend"),
    filename: "[name].js",
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: {
          loader: "babel-loader",
        },
      },
    ],
  },
  optimization: {
    minimize: true,
  },
  plugins: [
    new webpack.DefinePlugin({
      "process.env": {
        NODE_ENV: JSON.stringify("production"),
      },
    }),
  ],
};