client/webpack.config.js

const path = require('path')
const HtmlWebpackPlugin = require('html-webpack-plugin')
const webpack = require('webpack')

module.exports = {
    entry: ['react-hot-loader/patch',
        'webpack-hot-middleware/client',
        path.resolve(__dirname, 'src', 'index.js')],
    output: {
        path: path.resolve(__dirname, 'dist'),
        filename: 'bundle.js',
        publicPath: '/'
    },
    devtool: 'inline-source-map',
    mode: 'development',
    module: {
        rules: [
            {
                test: /\.jsx?/,
                exclude: /node_modules/,
                use: {
                    loader: 'babel-loader',
                    options: {
                        presets: [['@babel/preset-env', {
                            useBuiltIns: 'entry',
                            corejs:{ version: "3.10", proposals: true },
                            targets: { esmodules: true }
                        }], '@babel/preset-react']
                    }
                }
            },
            {
                test: /\.s[ac]ss$/i,
                use: ['style-loader', 'css-loader', 'sass-loader'],
            }
        ]
    },
    plugins: [
        new webpack.HotModuleReplacementPlugin(),
        new HtmlWebpackPlugin({
            template: path.resolve(__dirname, 'src', 'index.ejs')
        })
    ]
}