webpack.config.js

const HtmlWebPackPlugin = require('html-webpack-plugin');
const CopyWebpackPlugin = require('copy-webpack-plugin');
const webpack = require('webpack');

module.exports = {
  entry: {
    main: './src/index.js',
    background: './src/background.js',
  },
  watch: true,
  watchOptions: {
    aggregateTimeout: 300,
    poll: 1000,
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: [/node_modules/],
        use: {
          loader: 'babel-loader',
        },
      },
      {
        test: /\.html$/,
        use: [
          {
            loader: 'html-loader',
            options: { minimize: true },
          },
        ],
      },
      {
        test: /\.css$/,
        use: [{ loader: 'style-loader' }, { loader: 'css-loader' }],
      },
    ],
  },
  plugins: [
    new webpack.IgnorePlugin(/^\.\/background/),
    new HtmlWebPackPlugin({
      template: './src/index.html',
      filename: './index.html',
    }),
    new CopyWebpackPlugin([
      { from: 'manifest.json' },
      { from: 'src/background.js' },
      { from: 'icons', to: 'icons' },
    ]),
  ],
};