cra-template-node-express/template/src/server/index.js

You can use the template using the below command.

const webpack = require('webpack');
const middleware = require('webpack-dev-middleware');
const hotMiddleware = require('webpack-hot-middleware');
const express = require('express');
const path = require('path');

const app = express();
const webpackConfig = require('./webpack.config');
const compiler = webpack(webpackConfig);

if (webpackConfig.mode === 'production') {
    app.use(express.static(path.join(__dirname, 'dist')));
    const routes = require('./routes');
    app.use(routes());
} else {
    app.use(middleware(compiler));
    app.use(hotMiddleware(compiler));

    require('node-hot')
        .configure({
            exclude: [
                /[\/\\]node_modules[\/\\]/,
            ],
        });

    app.use((req, res, next) => {
        require('./routes').handle(req, res, next);
    });
}

const port = process.env.PORT || 3000;

app.listen(port, () => {
    console.log(`Listening on port ${port}...`);
});