webpack-demo.config.js

const HtmlWebpackPlugin = require('html-webpack-plugin');

const path = require('path');

module.exports = {
  mode: process.env.NODE_ENV || 'development',

  entry: './src/index.tsx',
  output: {
    filename: 'main.js',
    path: path.resolve(__dirname, 'demo'),
  },
  devServer: {
    contentBase: path.resolve(__dirname, 'demo'),
    port: 3000,
    hot: true,
  },

  module: {
    rules: [
      {
        test: /\.tsx?$/,
        use: [
          {
            loader: 'ts-loader',
            options: {
              onlyCompileBundledFiles: true,
              compilerOptions: {
                declaration: false,
              },
            },
          },
        ],
      },
      {
        test: /\.scss$/,
        use: [
          { loader: 'style-loader' },
          { loader: 'css-loader' },
          {
            loader: 'postcss-loader',
            options: {
              ident: 'postcss',
              plugins: () => [
                require('postcss-preset-env')({
                  overrideBrowserslist: ['> 1%', 'last 3 versions', 'Firefox ESR', 'Opera 12.1'],
                }),
              ],
            },
          },
          { loader: 'sass-loader' },
        ],
      },
      {
        test: /\.css$/,
        use: [{ loader: 'style-loader' }, { loader: 'css-loader' }],
      },
    ],
  },
  resolve: {
    extensions: ['.tsx', '.ts', '.js', '.scss', '.css'],
    symlinks: false,
    cacheWithContext: false,
  },
  plugins: [
    new HtmlWebpackPlugin({
      template: 'src/index.html',
    }),
  ],
};