When we developed our server-side code, we used packages from the npmjs.com registry. These packages were initially intended only for server-side code. Soon, front-end developers realized the power of all these server-side packages, and wanted to utilize them on the client.

This becomes an issue because CommonJS, with its synchronous loading, does not work well on the browser. It would take a long time to load because the modules that are required are not available on the client, and must be downloaded when the page is first accessed. So if a module has an extended dependency tree of over 100 modules, it'd have to download 100 modules before the page/application can be loaded. Since web pages are rarely kept open for a long period of time, the initial load would usually not be worthwhile to the end user, and they will abandon the site.

There are two different solutions to this issue:

• Module bundling
• Asynchronous module loading