import * as React from "react";
import { IOWidget, Options, Fun } from "../shared/widget";
export interface DropdownProps<a> {
    options?: Options;
    selected?: a;
    input: a[];
    to_string: Fun<a, string>;
    on_done: (output: a | null) => void;
}
export interface DropdownState<a> {
}
export declare class Dropdown<a> extends React.Component<DropdownProps<a>, DropdownState<a>> {
    constructor(props: DropdownProps<a>, context: any);
    render(): JSX.Element;
}
export declare let dropdown: <a>(to_string: Fun<a, string>, options?: Options | undefined) => IOWidget<[a[], a | undefined], a | null>;