/**
 * Makes the first character of a string uppercase
 */
export declare function upperFirst(str: string): string;
interface HTMLExpandElement extends HTMLElement {
    _parent?: (Node & ParentNode & HTMLElement) | null;
    _initialStyle: {
        transition: string;
        overflow: string | null;
        height?: string | null;
        width?: string | null;
    };
}
export default function (expandedParentClass?: string, x?: boolean): {
    beforeEnter(el: HTMLExpandElement): void;
    enter(el: HTMLExpandElement): void;
    afterEnter: (el: HTMLExpandElement) => void;
    enterCancelled: (el: HTMLExpandElement) => void;
    leave(el: HTMLExpandElement): void;
    afterLeave: (el: HTMLExpandElement) => void;
    leaveCancelled: (el: HTMLExpandElement) => void;
};
export {};