webpack.config.js

const path = require('path');
const webpack = require('webpack');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const CssMinimizerPlugin = require("css-minimizer-webpack-plugin");
//const NodePolyfillPlugin = require("node-polyfill-webpack-plugin")

module.exports = {
  mode: 'development',
  devServer: {
    proxy: {
      "/.netlify": {
        target: "http://localhost:9000",
        pathRewrite: { "^/.netlify/functions": "" }
      }
    }
  },
  resolve: {
    // see below for an explanation
    alias: {
      svelte: path.resolve('node_modules', 'svelte/src/runtime') // Svelte 3: path.resolve('node_modules', 'svelte')
    },
    extensions: ['.mjs', '.js', '.svelte', '.scss'],
    mainFields: ['svelte', 'browser', 'module', 'main'],
    conditionNames: ['svelte', 'browser', 'import'],
    fallback: {
      http: require.resolve('http-browserify'),
      https: require.resolve('https-browserify'),
      stream: require.resolve('stream-browserify'),
      //buffer: require.resolve('buffer/'),
      util: require.resolve("util/")
    }
  },
  entry: {
    bundle: path.resolve(__dirname, 'index.js')
  },
  output: {
    path: path.resolve(__dirname, 'dist'),
    filename: '[name].js'
  },
  plugins: [
    new MiniCssExtractPlugin({
      filename: '[name].[contenthash:8].min.css',
      chunkFilename: '[name].[contenthash:8].min.css',
    }),
    // new OptimizeCssAssetsPlugin({
    //   assetNameRegExp: /\.css$/g,
    //   cssProcessor: require('cssnano'),
    //   cssProcessorPluginOptions: {
    //     preset: ['default', { discardComments: { removeAll: true } }]
    //   },
    //   canPrint: true
    // }),
    new CssMinimizerPlugin(),
    // fix "process is not defined" error:
    new webpack.ProvidePlugin({
      process: 'process/browser',
      Buffer: ['buffer', 'Buffer']
    }),
    //new NodePolyfillPlugin()
  ],
  module: {
    rules: [
      {
        test: /\.(html|svelte)$/,
        use: 'svelte-loader'
      },
      {
        // required to prevent errors from Svelte on Webpack 5+, omit on Webpack 4
        test: /node_modules\/svelte\/.*\.mjs$/,
        resolve: {
          fullySpecified: false
        }
      },
      {
        test: /\.(sa|sc|c)ss$/,
        use: [
          'style-loader',
          MiniCssExtractPlugin.loader,
          'css-loader',
          {
            loader: 'sass-loader',
            options: {
              sassOptions: {
                includePaths: [
                  './theme',
                  './node_modules'
                ]
              }
            }
          }
        ]
      }
    ]
  }
};