Toggling CSS classes is fundamental for creating interactive UI elements like dropdown menus, modal dialogs, and state-based styling. With over 25 years of experience in software development and as the creator of CoreUI, I’ve implemented class toggling in numerous interactive components and animation systems. From my expertise, the most efficient approach is using the classList.toggle() method which adds the class if absent or removes it if present. This method provides clean, readable code while handling the conditional logic automatically.

Creating custom event emitters allows you to build modular, reactive components that communicate through events rather than direct method calls. As the creator of CoreUI, a widely used open-source UI library, and with over 25 years of experience in software development, I’ve designed countless Node.js services where custom event emitters provide clean separation of concerns. The most effective approach is extending the EventEmitter class to create specialized event emitters that encapsulate specific business logic. This pattern enables loose coupling and makes your code more testable and maintainable.

Getting elements by class name allows you to select and manipulate multiple elements that share the same CSS class, perfect for batch operations. As the creator of CoreUI, a widely used open-source UI library, I’ve used class-based selection extensively for styling updates and event handling across multiple components. From my expertise, document.getElementsByClassName() is the most straightforward method for selecting elements by class. This approach returns a live HTMLCollection that automatically updates when the DOM changes.