import * as React from 'react';
import 'union-design/lib/back-top/styles/css';
export interface BackTopProps {
    /**
     * 类型
     */
    duration?: number;
    target?: () => HTMLElement;
    visibilityHeight?: number;
    onClick?: () => {};
    style?: object;
}
declare const BackTop: React.FC<BackTopProps>;
export default BackTop;