Example of how to use the loadBundles function as defined in https://gist.github.com/svdoever/aebdbc6acf0bd15e354c18af9ed1bd47

usebundles.js

process.env.ComponentServerBundles = JSON.stringify({
    default: './server-bundle',
    pwa: './server-bundle',
    pwaremote: 'http://myserver.com/server-bundle.js'
});

// Handy for debugging to use a direct require so Visual Studio code can set breakpoints in the code
// of the bundle we are debugging.
let bundle_to_debug = require('./server-bundle');
if (process.env.NODE_ENV === 'production') {
    bundle_to_debug = undefined;
}

const path = require('path');

// componentSpecifier is a string in the format "pwa:myComponent", if only "myComponent" is specified the
// component in the "default" bundle is assumed.
function getComponent(componentSpecifier) {
    console.log(`Requested component: ${componentSpecifier}`);
    let bundleName, componentName;
    if (componentSpecifier.includes(':')) {
        const parts = componentSpecifier.split(':');
        if (parts[0] === '') {
            bundleName = 'default';
            componentName = parts[1];
        } else {
            bundleName = parts[0];
            componentName = parts[1];
        }
    } else {
        bundleName = 'default';
        componentName = componentSpecifier;
    }

    if (typeof bundle_to_debug !== 'undefined' && bundle_to_debug) {
        console.log(`Using 'bundle_to_debug' to resolve requested component '${componentSpecifier}' as component '${componentName}'.`);
        component = bundle_to_debug[componentName];
        bundleName = 'bundle_to_debug';
    } else {
        if (!bundles[bundleName]) {
            throw new Error(`getComponent(): Bundle '${bundleName}' not found.`);
        }
    
        component = bundles[bundleName][componentName];
    }

    if (!component) {
        throw new Error(`getComponent(): component '${componentName}' not found in bundle '${bundleName}'.`);
    }

    if (typeof component !== "function") {
        throw new Error(`getComponent(): component '${componentName}' is found in bundle '${bundleName}' but it is not a function.`);
    }

    return component;
}

let bundleLoaderPromises; // all promises that must be resolved so we know all required server bundles are loaded
let bundles = {};

if (typeof bundle_to_debug == 'undefined') {
    if (!process.env.ComponentServerBundles) {
        console.error("Environment variable process.env.ComponentServerBundles is missing. Should contain definition of bundles, i.e.: { pwa: './server-bundle.js', stories: 'http://myserver.com/story-bundle.js' }");
        process.exit(1);
    }

    let bundlesConfiguration;
    try {
        bundlesConfiguration = JSON.parse(process.env.ComponentServerBundles);

    } catch(error) {
        console.error(`Failed to parse process.env.ComponentServerBundles due to error: ${error.message}.\nCurrent value: ${process.env.ComponentServerBundles}`);
        process.exit(1);
    }

    bundleLoaderPromises = loadBundles(bundlesConfiguration, bundles);
} else {
    // We don't need to load bundles, overridden by: let bundle_to_debug = "./server-bundle.js"
    // Create an empty array for the bundle promises so Promise.all(bundleLoaderPromises) directly resolves.
    console.log("Using configured bundle_to_debug");
    bundleLoaderPromises = [];
}

Promise.all(bundleLoaderPromises).then(() => {
  // Do something with the bundles, a component can be retrieved like:
  // let myComponent = getComponent("pwa:MyComponent")
}).catch(reason => { 
    console.error(reason.message);
    process.exit(1);
});