Advanced Event Emitter: Managing Memory and Listeners

Monitor maxListeners, use .once() for single-use events, and always remove listeners in cleanup phases to prevent memory leaks.

Each EventEmitter listener is a closure stored in an internal array. If you add listeners inside a request handler and never remove them, the array grows forever, and the objects captured in the closure are never garbage collected. Node.js issues a warning at 10 listeners by default as a safety measure. In a senior context, you must implement explicit cleanup logic, especially when using AbortController for cancellation.