/**
 * Whether the parent listens for one of the current component's events: Vue 3 keeps
 * listeners in the vnode props (onError, onErrorOnce), Vue 2.7 in $listeners. Call in
 * setup(); the returned check reads the listeners when it runs.
 */
export declare function listenerCheck(): (name: string) => boolean;
/**
 * Logs a failure the component also reports through `event` and its `#error` slot, but only
 * when the app handles neither: a handled failure stays out of the console (and out of error
 * monitoring that collects console.error). Call in setup().
 */
export declare function errorLogger(slots: Record<string, unknown>, event?: string): (label: string, message: string) => void;