webpack.config.js

const path = require('path');
const mode = process.env.NODE_ENV;
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const webpack = require('webpack');
module.exports = {
  devServer: {
    publicPath: '/build/',
    proxy: {
      '/callback': 'http://localhost:3000',
      '/api': 'http://localhost:3000',
      '/verify': 'http://localhost:3000',
      '/twitter': 'http://localhost:3000',
    },
    port: 8080,
    hot: true,
  },
  entry: ['./client/index.js'],
  output: {
    path: path.resolve(__dirname, 'build'),
    filename: 'bundle.js',
    publicPath: 'http://localhost:8080/build/',
  },
  mode,
  plugins: [
    new MiniCssExtractPlugin(),
    new webpack.HotModuleReplacementPlugin(),
  ],
  module: {
    rules: [
      {
        test: /\.jsx?/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['@babel/preset-env', '@babel/preset-react'],
          },
        },
      },

      {
        test: /\.s[ac]ss$/i,
        use: [
          // Creates `style` nodes from JS strings
          //'style-loader',
          MiniCssExtractPlugin.loader,
          // Translates CSS into CommonJS
          'css-loader',
          // Compiles Sass to CSS
          'sass-loader',
        ],
      },
    ],
  },
};