The module pattern uses closures to create private and public members, providing encapsulation and namespace management in JavaScript. As the creator of CoreUI with 26 years of JavaScript development experience, I’ve used module patterns extensively before ES6 modules to organize code in large applications, creating clean APIs with private implementation details for millions of users.

The most maintainable approach uses IIFE (Immediately Invoked Function Expression) or ES6 modules for encapsulation.