webpack.config.js

const path = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
const webpack = require('webpack');

module.exports = {
    entry: './client/index.tsx',
    mode: process.env.NODE_ENV,
    output: {
        path: path.resolve(__dirname, 'dist'),
        filename: 'bundle.js',
    },
    resolve: {
        extensions: [".ts", ".tsx", ".js", ".jsx"]
    },
    module:{
      rules: [
          {
            test: /\.(jsx|js|ts|tsx)$/,
            exclude: /node_modules/,
            use: {
            loader: 'babel-loader',
            },
          },
          {
            test: /\.s?css$/,
            exclude: /node_modules/,
            use: ['style-loader', 'css-loader', 'sass-loader'],
          },
        ],
    },
    plugins: [
        new HtmlWebpackPlugin({
            template: "./client/index.html",
        }),
        new MiniCssExtractPlugin(),
        new webpack.DefinePlugin({
            "process.env": {
              "NODE_ENV": JSON.stringify(process.env.NODE_ENV)
            }
        })
    ],
    devServer: {
        historyApiFallback: true,
        port: 8080,
        publicPath: '/',
        contentBase: path.resolve(__dirname, 'build'),
        proxy: {
            '/': 'http://localhost:3000'
        },
        watchOptions: {
            poll: 1000,
            aggregateTimeout: 300
        }
    }
};