/**
 * dismissable-layer - a global stack of dismissable overlays (dropdowns,
 * popovers, dialogs). Escape and outside-pointer dismiss only the TOP layer, so
 * a menu opened inside a dialog closes the menu first and the dialog second -
 * the ordering users expect from nested overlays. One set of document listeners
 * is shared by every layer instead of each component wiring its own.
 */
type Reason = 'escape' | 'outside';
/** One element, several elements, or a getter of either. A pointerdown counts
 *  as "inside" when it lands in ANY of them (e.g. a popover's panel AND its
 *  trigger, so clicking the trigger doesn't immediately re-dismiss). */
export type DismissTarget = HTMLElement | null | ReadonlyArray<HTMLElement | null>;
export type DismissableOptions = {
    /** The panel element(s); a pointerdown outside ALL of them dismisses the layer.
     *  Pass multiple (e.g. panel + trigger) so clicking the trigger doesn't
     *  immediately re-dismiss what it just opened. */
    element: () => DismissTarget;
    onDismiss: (reason: Reason) => void;
    /** Dismiss on Escape when topmost. Default true. */
    closeOnEscape?: boolean;
    /** Dismiss on outside pointerdown when topmost. Default true. */
    closeOnOutside?: boolean;
};
export type DismissableLayer = {
    activate: () => void;
    release: () => void;
};
/** Register a dismissable layer. Inert until `activate()`. */
export declare function createDismissableLayer(options: DismissableOptions): DismissableLayer;
/** Test/introspection helper: current number of active layers. */
export declare function dismissableDepth(): number;
/**
 * Close-on-scroll for popovers that are position:fixed and anchored by a
 * one-time measurement taken when they open. Scrolling an ancestor slides the
 * anchor out from under them, so they have to close - but scrolling INSIDE
 * them (a long menu, a facet list) must not, which is what a bare capture-phase
 * window listener gets wrong: inner scroll containers don't bubble, so the
 * capture listener sees them and dismisses the panel the user is scrolling.
 *
 * Returns the unsubscribe function.
 */
export declare function onScrollOutside(element: () => DismissTarget, onOutside: () => void): () => void;
export {};