/** Cancels what runs on the elements. Collected first, so styles are flushed only once. */
export declare const cancel: (elements: (Element | null)[]) => void;
/**
 * Switches the layout through `apply` and animates the rail and its items from where they were.
 * Resolves when the rail has finished moving.
 */
export declare const morph: (rail: HTMLElement, apply: () => void, timing: KeyframeAnimationOptions, 
/** Timing for the rail's own width, when it moves differently from its items. */
railTiming?: KeyframeAnimationOptions) => Promise<void>;
/**
 * Grows the rail out of nothing or shrinks it away, for a rail that is hidden when collapsed.
 * Shrinking holds the end, so the rail stays gone until it is hidden.
 */
export declare const resize: (rail: HTMLElement, grow: boolean, timing: KeyframeAnimationOptions) => Promise<void | Animation>;