import { PipeTransform } from '@angular/core';
/**
 * pipe allows clean component specific transformation of value without having to create a seperate pipe
 * for each set of transformation logic to improve performance. also useful for when same logic needed in template and component.ts
 * @param value the value to transform
 * @param callback the transformation function to run on value
 * useful if callback passed needs more data than just the value
 * @example
 * // if we were to run this callback directly in the template performance would suffer. YAY pipes!!!
 * {{ 'hello' | callback : (value) => value + ' world' }}
 */
export declare class CallbackPipe implements PipeTransform {
    transform(value: any | any[], callback: PipeCallback): any;
}
export declare type PipeCallback = (...value: any[]) => any;