import type { sourceType } from '../core/constants';
export declare function addObserver(observer: any, propertyName: any): any;
export type ObserverParams = {
    watch?: string | string[];
    filter?: (value: any, params: any) => boolean;
    action?: (value: any, params: any) => any | Promise<any>;
    source?: sourceType | sourceType[];
    hasOldValue?: boolean;
};
export type Observer = ObserverParams[] & {
    type?: symbol;
};
export default function CustomerObserver(observers: ObserverParams | ObserverParams[]): Observer;