When an event is mandatory, what must be specified to handle the event?

When an event is mandatory, specifying a Client Action is essential for handling that event. A Client Action is a piece of code that executes on the client-side, typically in response to user interactions or other triggers in a reactive web application. By associating a mandatory event with a Client Action, you establish a clear and functional way to define how the application should respond when that event occurs. This ensures that the application can handle the event effectively, providing the necessary logic and behavior.

A Client Action can encapsulate various logic, such as modifying UI elements, making API calls, or updating application state. By assigning a mandatory event to a specific Client Action, developers can ensure that the necessary application flow is implemented whenever the event is triggered.