Emitter

• Type:

  function Emitter<Events extends Record<EventType, unknown>>(
    all?: EventHandlerMap<Events>,
  ): EmitterInstance<Events>;

Event dispatcher used by the framework, fully consistent with @mptool/enhance.

Creating an instance

Call Emitter() to get an Emitter instance.

Tips

Emitter accepts an Events object as a generic argument so TypeScript can infer event types.

import { Emitter } from "@mptool/skyline-enhance";

type Events = {
  foo: string;
  bar?: number;
  baz: void;
};

const emitter = Emitter<Events>(); // inferred as EmitterInstance<Events>

emitter.on("foo", (e) => {}); // 'e' has inferred type 'string'

emitter.emit("foo", 42); // Error: Argument of type 'number' is not assignable to parameter of type 'string'. (2345)

emitter.on("baz"); // 'baz' should not contain event object

emitterInstance.all

• Type: all: EventHandlerMap<Events>

Map from event names to registered handlers.

emitterInstance.on

Register an event handler for the given type.

• Type:

  function on<Key extends keyof Events>(type: Key, handler: GenericEventHandler): void;

• Parameters:

  • type: string | symbol event type to listen for, or '*' to listen for all events
  • handler: Function function called in response to the given event

emitterInstance.off

Remove the event handler for the given type. If handler is omitted, all handlers for the given type are removed.

• Type:

  function off<Key extends keyof Events>(type: Key, handler?: GenericEventHandler): void;

• Parameters:

  • type: string | symbol event type to remove the listener for, or '*' to remove all listeners
  • handler: Function handler function to remove

emitterInstance.emit

Invoke all handlers for the given type. If '*' exists, it is called after all other handlers have finished.

Warning

Manually emitting '*' is not supported

• Type:

  function emit<Key extends keyof Events>(type: Key, event?: Events[Key]): void;

• Parameters:

  • type: string | symbol event type to emit
  • event: any value; passing an object is recommended

emitterInstance.emitAsync

Invoke all handlers for the given type asynchronously. If '*' exists, it is called after all other handlers have finished; after all handlers have completed, its own callback is triggered.

Warning

Manually emitting '*' is not supported

• Type:

  function emitAsync<Key extends keyof Events>(type: Key, event?: Events[Key]): Promise<void>;

• Parameters:

  • type: string | symbol event type to emit
  • event: any value; passing an object is recommended

Global instance

The framework exports a global emitter instance (userEmitter) that can be used for communication between any modules:

import { emitter } from "@mptool/skyline-enhance";

emitter.on("user-login", () => {});
emitter.emit("user-login");