Types

All of these types live in src/core/types.ts and form the foundation of the library’s type system.

Type	Description
Handler<T>	(payload: T) => void — signature of an event handler.
EventMap	Record<string, unknown> — generic constraint for user-defined events.
TabusMessage<T>	Shape of the internal message: { tabId, event, payload }.
InternalEvents	{ "tab:join": { tabId }, "tab:leave": { tabId } } — automatically emitted lifecycle events.
FullEventMap<T>	Combines the user’s events (T) with InternalEvents; used in the signatures of on() / off().
TabusOptions	{ throttle?: number; trailing?: boolean } — see Options.

Handler<T>

type Handler<T = unknown> = (payload: T) => void;

The signature any function passed to on() or off() must satisfy.

EventMap

type EventMap = Record<string, unknown>;

Generic constraint that the event type you pass to Tabus<Events> must satisfy. Any object with string keys works:

type MyEvents = {
  data: { value: number };
  reset: void;
};

TabusMessage<T>

interface TabusMessage<T = unknown> {
  tabId: string;
  event: string;
  payload: T;
}

Shape of the internal message that travels through the transport. It’s the type received by send() and by listeners registered with onMessage() on ITransport.

InternalEvents

type InternalEvents = {
  "tab:join": { tabId: string };
  "tab:leave": { tabId: string };
};

The two lifecycle events that Tabus emits automatically. See Lifecycle events.

FullEventMap<T>

type FullEventMap<T extends EventMap> = T & InternalEvents;

Combines your custom events with InternalEvents. It’s the actual type used by the signatures of on() and off(), so you can always subscribe to "tab:join" / "tab:leave" in addition to your own events, without declaring them yourself.

Next step

• Tabus class: where these types are used in practice.
• Exports: what’s publicly exported from the package.