webpack.config.js

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

const htmlPlugin = new HtmlWebPackPlugin({
  template: './client/index.html',
  filename: './index.html',
});

module.exports = () => (
  {
    entry: './client/index.jsx',
    output: { // NEW
      path: path.join(__dirname, 'dist'),
      filename: '[name].js',
    }, // NEW Ends
    plugins: [htmlPlugin],
    resolve: {
      extensions: ['.js', '.jsx'],
    },
    module: {
      rules: [
        {
          test: /\.(js|jsx)$/,
          exclude: /node_modules/,
          use: ['babel-loader', 'eslint-loader'],
        },
        {
          test: /\.(png|svg|jpg|gif)$/,
          loader: 'file-loader',
          options: { name: '/static/[name].[ext]' },
        },
        {
          test: /\.(s[ac]ss)$/i,
          use: ['style-loader', 'css-loader', 'sass-loader'],
        },
        {
          test: /\.mp3$/,
          loader: 'file-loader',
        },
      ],
    },
  }
);