webpack.config.js

const path = require('path');
const webpack = require('webpack');
const dotenv = require('dotenv');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const CompressionPlugin = require('compression-webpack-plugin');
const BrotliPlugin = require('brotli-webpack-plugin');

process.env.NODE_ENV = process.env.NODE_ENV || 'development';
if (process.env.NODE_ENV === 'development') {
  dotenv.config({ path: '.env.development' });
}

module.exports = (env) => {
  const isProduction = env === 'production';

  return {
    entry: './client/src',
    output: {
      path: path.join(__dirname, 'public', 'dist'),
      publicPath: '/dist/',
      filename: 'bundle.js',
      chunkFilename: '[name].bundle.js',
    },
    module: {
      rules: [
        {
          test: /\.js$/,
          exclude: /node_modules/,
          loader: ['babel-loader', 'eslint-loader']
        },
        {
          test: /\.s?css$/,
          use: [
            {
              loader: MiniCssExtractPlugin.loader,
              options: { url: false }
            },
            'css-loader',
            'sass-loader'
          ]
        },
        {
          test: /\.(png|jpg|gif|otf)$/i,
          use: [
            {
              loader: 'url-loader',
              options: {
                limit: 8192
              }
            }
          ]
        }
      ]
    },
    plugins: getPlugins(isProduction),
    devtool: isProduction ? 'source-map ' : 'inline-source-map',
    devServer: {
      contentBase: [path.join(__dirname, 'public'), path.join(__dirname, 'users')],
      historyApiFallback: true,
      publicPath: '/dist/',
      proxy: {
        '/api': 'http://localhost:3001',
        secure: false
      }
    }
  };
};

/**
 * Returns all availables plugins for the current env
 * 
 * @param {Determinates if current env is production } isProduction 
 */
const getPlugins = (isProduction) => {
  const plugins = [
    new MiniCssExtractPlugin({
      filename: 'styles.css',
    }),
    new webpack.DefinePlugin({
      'process.env.FIREBASE_API_KEY': JSON.stringify(process.env.FIREBASE_API_KEY),
      'process.env.FIREBASE_AUTH_DOMAIN': JSON.stringify(process.env.FIREBASE_AUTH_DOMAIN),
      'process.env.FIREBASE_DATABASE_URL': JSON.stringify(process.env.FIREBASE_DATABASE_URL),
      'process.env.FIREBASE_PROJECT_ID': JSON.stringify(process.env.FIREBASE_PROJECT_ID),
      'process.env.FIREBASE_STORAGE_BUCKET': JSON.stringify(process.env.FIREBASE_STORAGE_BUCKET),
      'process.env.FIREBASE_MESSAGING_SENDER_ID': JSON.stringify(process.env.FIREBASE_MESSAGING_SENDER_ID)
    })
  ];

  // Run Compression Plugins only in production mode
  if (isProduction) {
    plugins.push(
      new CompressionPlugin({
        filename: '[path].gz[query]',
        algorithm: 'gzip',
        test: /\.js$|\.css$|\.html$/,
        threshold: 10240
      }),
      new BrotliPlugin({
        asset: '[path].br[query]',
        test: /\.js$|\.css$|\.html$/,
        threshold: 10240,
      })
    );
  }

  return plugins;
};