Foundations of a Frontend Platform - Custom Core Libraries

Core Libraries are the Frontend equivalent of how you expose your underlying infrastructure on your Internal Development Platform. 

Besides your domain-specific code that your Product teams build, there's usually a need to centralize infrastructural functionality into Core Libraries. A common example of this, that everybody understands, is Logging. You don't want every product team to build their own Client-side Logging service that talks to their Log server of choice, where everybody formats their log messages in their own way, using their own identifier to track what happened. These are typical things you want to have standardized throughout your entire organization in order to have full end-to-end traceability.

If you want live updates to be delivered to your Frontend application, you don't want every product team to set up their own way of handling WebSockets or other form of Server Push, but rather use a central service that is robust and secure, works with scaleable infrastructure on the server and uses central logging. The client-side library to handle Server Push, where Product features can easily hook into, can be built and maintained centrally by a Platform team.

If you happen to be leveraging a Hybrid Mobile App, you may want to have a standard way of falling back to Web technology for functions you have built in Native technology and exposed on a Native bridge. Or a standard way of informing a user that a certain function is not available in the browser. Thus you may want to encapsulate this functionality into a Core Library that handles Native functions in a standardized way.

Depending on your setup, infrastructure and organization, you probably have specific items you want to offer to your product teams, in order to provide standardized, secure and compliant functionality that speeds up their development.