Webpack

                                Необходимые зависимости в файле:
package.json

{
  "name": "webpack_dimitriytiho",
  "version": "1.0.0",
  "description": "",
  "main": "postcss.config.js",
  "scripts": {
    "dev": "webpack --mode development",
    "watch": "webpack --mode development --watch",
    "minwatch": "webpack --mode production --watch",
    "prod": "webpack --mode production"
  },
  "author": "dimitriytiho",
  "license": "ISC",
  "devDependencies": {
    "autoprefixer": "^9.8.0",
    "css-loader": "^3.6.0",
    "mini-css-extract-plugin": "^0.8.2",
    "node-sass": "^4.14.1",
    "optimize-css-assets-webpack-plugin": "^5.0.3",
    "postcss-cli": "^6.1.3",
    "postcss-loader": "^3.0.0",
    "sass-loader": "^8.0.2",
    "style-loader": "^1.2.1",
    "terser-webpack-plugin": "^2.3.7",
    "uglifyjs-webpack-plugin": "^2.2.0",
    "url-loader": "^3.0.0",
    "webpack": "^4.43.0",
    "webpack-cli": "^3.3.11"
  },
  "dependencies": {
    "bootstrap": "^4.6.0"
  }
}



Далее установить node_modules


webpack.config.js

const webpack = require('webpack'),
    path = require('path'),
    MiniCssExtractPlugin = require('mini-css-extract-plugin'),
    OptimizeCssAssetsPlugin = require('optimize-css-assets-webpack-plugin'),
    TerserPlugin = require('terser-webpack-plugin'),
    autoprefixer = require('autoprefixer')

module.exports = {
  entry: {
    'app': './source/index.js'
    //'content': './source/content.js',
  },
  output: {
    path: path.resolve(__dirname, 'assets'),
    filename: 'js/[name].js'
  },
  optimization: {
    minimizer: [
      new OptimizeCssAssetsPlugin({}),
      new TerserPlugin()
    ]
  },
  plugins: [
    new MiniCssExtractPlugin({
      filename: 'css/[name].css'
    }),
    new webpack.LoaderOptionsPlugin({
      options: {
        postcss: [
          autoprefixer()
        ]
      }
    })
  ],
  //devtool: 'source-map',
  module: {
    rules: [
      {
        test: /\.scss$/,
        use: [
          MiniCssExtractPlugin.loader,
          {
            loader: 'css-loader',
            options: {
              sourceMap: false
            }
          },
          {
          loader: 'postcss-loader',
          options: {
            plugins: [
              autoprefixer({
                //browsers:['ie >= 8', 'last 4 version']
              })
            ],
            sourceMap: false
          }},
          {
            loader: 'sass-loader',
            options: {
              sourceMap: false
            }
          }
        ]
      },
      {
        test: /\.(png|jpg|jpeg|gif|svg)$/i,
        use: [
          'url-loader'
        ]
      }
    ]
  }
}


Файлы для сборки в папке source, скомпилированные файлы в папке assets
Далее в консоле команду npm run minwatch или команды: dev, watch, prod
Список