import * as i0 from "@angular/core";
export interface Option<K, V> {
    key: K;
    label: V;
    disabled?: boolean;
}
export interface OptionGroup<T extends Option<any, any>> {
    label: string;
    options: T[];
    disabled?: boolean;
}
export type OptionBase<T extends Option<any, any>> = T | OptionGroup<T>;
export declare class DropdownUtils<K = string | null, V = string, T extends Option<K, V> = Option<K, V>> {
    flattenOptions(options: OptionBase<T>[] | undefined, mustHaveLabel: boolean): T[];
    /**
     * Returns true if argument is an {@link OptionGroup}.
     * @param option the object to check.
     */
    isGroup(option: OptionBase<T>): option is OptionGroup<T>;
    deepEqual(original: any, change: any): boolean;
    static ɵfac: i0.ɵɵFactoryDeclaration<DropdownUtils<any, any, any>, never>;
    static ɵprov: i0.ɵɵInjectableDeclaration<DropdownUtils<any, any, any>>;
}