/** The two bounds a range calendar edits. `end` is null while a range is open. */
export interface DateRangeSelection {
    start: Date | null;
    end: Date | null;
}
/**
 * The selection after clicking `date`.
 *
 * One rule, no modes: a click either OPENS a range (when none is open) or
 * CLOSES the open one. Selecting a single day is clicking the same day twice —
 * there is deliberately no separate single-day mode, because a mode that
 * changes what a click means is a mode the user can get stuck in with no way
 * to express a range at all.
 *
 * Bounds come back ordered, so clicking the later day first is just another way
 * to select rather than an error the caller has to undo.
 */
export declare function nextRangeSelection(current: DateRangeSelection, date: Date): DateRangeSelection;
/**
 * The end a range would CLOSE on if the pointer stopped at `hovered` — what a
 * calendar fills in to show the span before it is committed.
 *
 * `null` unless a range is actually open, and open is tested exactly the way
 * {@link nextRangeSelection} tests it. That shared test is the point of putting
 * this here: a preview that disagreed with the click would show a span the next
 * click does not produce, and the two rules drifting apart is precisely what a
 * second copy of "is a range open" would eventually do.
 */
export declare function previewEndFor(current: DateRangeSelection, hovered: Date | null): Date | null;