import { PipeTransform } from '@angular/core';
import { RivSelect } from '../select/state';
import * as i0 from "@angular/core";
export declare class OptionGroupPipe<O extends RivSelect.BaseOption> implements PipeTransform {
    transform(value?: O[], header?: string): RivSelect.OptionGroup<O>[];
    static ɵfac: i0.ɵɵFactoryDeclaration<OptionGroupPipe<any>, never>;
    static ɵpipe: i0.ɵɵPipeDeclaration<OptionGroupPipe<any>, "rivOptionGroup", false>;
}