How does AngularJS handle large-scale directive architecture design?

Directives in AngularJS encapsulate DOM logic and should be designed as reusable, isolated components.

At scale, directives become the foundation of UI architecture. They should use isolate scope, avoid direct DOM manipulation outside link function, and separate template, logic, and behavior. Poor directive design leads to tight coupling and performance degradation. Advanced architectures use directive composition for reusable UI systems.