EventBus

EventBus: object

Defined in: Core/EventBus.ts:43

Type Declaration

emit

emit: object = emitEventBus

Emits a message payload to one or more target event buses.

Uses a synchronous breadth-first trampoline queue to handle re-entrant emissions deterministically.

See

• EventBus.subscribe for subscribing to emitted messages.
• EventBus.forward for routing messages between event buses.

Example

EventBus.emit(busA, {
  kind: "userLoggedIn",
  value: { userId: "user-1" },
});

EventBus.emit([busA, busB], {
  kind: "userLoggedIn",
  value: { userId: "user-1" },
});

forward

forward: object = forwardEventBus

Forwards messages from one event bus to another (or multiple).

Forwarding a message back to a bus it already visited within the same emission throws an error naming the bus and message kind, breaking cycles such as A → B → A on the first repeat instead of delivering indefinitely.

See

• EventBus.emit for publishing messages directly.
• EventBus.subscribe for consuming events on a bus.

Example

const stop = EventBus.forward({
  from: authBus,
  to: analyticsBus,
  only: ["userLoggedIn"],
});

make

make: object = makeEventBus

Constructs a new EventBus instance.

See

• EventBus.emit for dispatching messages to an event bus.
• EventBus.subscribe for registering subscribers or sequence matchers.

Example

const bus = EventBus.make<AppMessages>({ id: "app" });

subscribe

subscribe: object = subscribeEventBus

Initiates subscriber registration on an event bus for all events, specific event kind(s), or sequence.

When called with only an event bus (EventBus.subscribe(bus)), observes every event defined on the bus schema. When called with event kinds, observes only matching events or sequences.

See

• EventBus.emit for dispatching messages to subscribers.
• EventBus.forward for bridging events across buses.

Example

// Schema-wide subscription:
const unsubscribe = EventBus.subscribe(appBus).tap((msg) => {
  console.log("Telemetry event:", msg.kind, msg.value);
});

// Targeted sequence subscription:
const sub = EventBus.subscribe(
  appBus,
  ["userLoggedIn", "checkoutStarted"],
  { ordered: true }
).collect((payloads) => {
  console.log("Checkout initiated by", payloads.userLoggedIn.userId);
});