Incorrect EventDispatcher’s type parameter of inherited classes

[shotamatsuda]

The types of Effect class and other classes that inherit EventDispatcher are currently defined as:

export class Effect extends EventDispatcher<import("three").Event>

However, the definitions of EventDispatcher and Event types are:

export class EventDispatcher<TEventMap extends {} = {}> {
  addEventListener<T extends Extract<keyof TEventMap, string>>(
    type: T,
    listener: EventListener<TEventMap[T], T, this>,
  ): void;

  dispatchEvent<T extends Extract<keyof TEventMap, string>>(
    event: BaseEvent<T> & TEventMap[T]
  ): void;
}

export interface Event<TEventType extends string = string, TTarget = unknown> {
  readonly type: TEventType;
  readonly target: TTarget;
}

This means Effect incorrectly expects events of “event type” "type" and "target" with the types of “event object” being string and unknown, respectively, which results in type errors when trying to call any of EventDispatcher’s functions or subclassing it.

A possible fix, without explicitly specifying the event types being used, is:

export class Effect extends EventDispatcher<Record<string, any>>

This will ensure keyof TEventMap resolves to string and TEventMap[T] to any, bypassing the type constraint issues and allowing EventDispatcher’s functions to be used without type errors.

Alternatively:

export class Effect extends EventDispatcher

This follows the default type behavior of EventDispatcher.

I suspect the type definition of EventDispatcher in @types/three was different in the past. Feel free to close this if you think it’s just a compatibility issue of @types/three.