GramIO API Reference / @gramio/composer/dist / EventContextOf

Type Alias: EventContextOf<T, E>

EventContextOf<T, E> = T extends object ? O & E extends keyof D ? D[E] : object : never

Defined in: composer/index.d.ts:410

Extracts the context type for a specific event from an EventComposer instance, combining global TOut (like ContextOf) and per-event TDerives[E].

Use this in custom event-specific methods (e.g. command, hears) instead of ContextOf<T> so that handlers registered via derive(event, handler) are visible in the handler's type:

Type Parameters

Type Parameter
T
E extends string

Example

const methods = defineComposerMethods({
  command<TThis extends ComposerLike<TThis>>(
    this: TThis,
    name: string,
    handler: Middleware<MsgCtx & EventContextOf<TThis, "message">>,
  ): TThis {
    return this.on("message", (ctx, next) => {
      if (ctx.text === `/${name}`) return handler(ctx, next);
      return next();
    });
  },
});

new Composer()
  .derive("message", () => ({ t: (s: string) => s }))
  .command("start", (ctx) => ctx.t("Hi!")); // ✅ t is visible