Type Alias MessageHandler<T, R>

MessageHandler: (data: T, ...other: any[]) => R | Promise<R>

A function that handles messages published to a specific Topic.

Message handlers are registered using MessageBus.subscribe or MessageBus.subscribeOnce. They are invoked whenever a message is published to the corresponding topic.

Type Parameters

T = unknown
The type of the payload data received by the handler.
R = unknown
The type of the value returned by the handler. Defaults to void, which means nothing is returned.

Type Declaration

- (data: T, ...other: any[]): R | Promise<R>
- Parameters
  - data: T
    The payload sent with the topic message.
  - ...other: any[]
    Optional additional message handler arguments injected by MessageInterceptor(s).
  Returns R | Promise<R>
  The handler's result, which may be returned synchronously or as a promise. Defaults to void, which means nothing is returned.

Example

bus.subscribe(UserCreatedTopic, async (user) => {
  await sendWelcomeEmail(user);
});