Webpack - Why is my bundle.js file minified by default?

Question

I am learning react, and the online course I am following uses webpack. I didn't add any minifying or uglyfying options to my webpack.config but still my bundle.js is minified. I am not sure why or how to turn it off. I have attached my webpack.config.js and package.json. Thanks for your help.

const path = require('path');

module.exports = {
  entry: './src/app.js',
  output: {
    path: path.join(__dirname, 'public'),
    filename: 'bundle.js'
  },
  module: {
    rules: [{
      loader: 'babel-loader',
      test: /\.js$/,
      exclude: /node_modules/
    }, {
      test: /\.s?css$/,
      use: [
        'style-loader',
        'css-loader',
        'sass-loader'
      ]
    }]
  },
  devtool: 'cheap-module-eval-source-map',
  devServer: {
    contentBase: path.join(__dirname, 'public'),
    historyApiFallback: true
  }
};

{
  "name": "expensify",
  "version": "1.0.0",
  "description": "learn react",
  "main": "index.js",
  "author": "powpowpow",
  "license": "MIT",
  "scripts": {
    "serve": "live-server public",
    "build": "webpack",
    "dev-server": "webpack-dev-server"
  },
  "dependencies": {
    "babel-cli": "^6.26.0",
    "babel-core": "^6.26.0",
    "babel-loader": "^7.1.4",
    "babel-plugin-transform-class-properties": "^6.24.1",
    "babel-preset-env": "^1.6.1",
    "babel-preset-react": "^6.24.1",
    "css-loader": "^0.28.11",
    "live-server": "^1.2.0",
    "node-sass": "^4.8.3",
    "normalize.css": "^8.0.0",
    "react": "^16.2.0",
    "react-dom": "^16.2.0",
    "react-modal": "^3.3.2",
    "react-router-dom": "^4.2.2",
    "sass-loader": "^6.0.7",
    "style-loader": "^0.20.3",
    "webpack": "^4.2.0",
    "webpack-cli": "^2.0.13",
    "webpack-dev-server": "^3.1.1"
  }
}

Answer 1

As you are using webpack 4

One of the ways is :

Inside package.json set scripts to either development or production mode

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

And now when you run npm run dev it will give you bundle.js but not minified.

But when you run npm run build it will give you a minified bundle