defineEmits is the <script setup> macro for declaring custom events that a component can emit, replacing the emits option and giving you type-safe emit functions with IDE autocompletion. As the creator of CoreUI with Vue development experience since 2014, I use defineEmits in every component that communicates with its parent through events, from simple click callbacks to complex form submission payloads. Declaring emits explicitly serves two purposes: it documents the component’s event API, and it enables Vue to distinguish between custom events and native DOM events on the root element. The TypeScript generic syntax provides the best developer experience with full type inference on the emitted payload.