import type { LineChartSeries } from '../LineChartContext';
interface UseLineChartActiveKeyResult {
    /**
     * Resolved active key after normalising stale values against the live
     * `seriesByKey` map. `null` whenever the controlled value points at a key
     * that no longer exists in `series`.
     */
    activeKey: string | null;
    /**
     * Setter that deduplicates per-pixel mousemove/hover events and forwards to
     * the controlled callback. Use this instead of writing state directly so
     * consumer callbacks don't fire with the same value frame after frame.
     */
    setActiveKey: (key: string | null) => void;
}
/**
 * Controlled/uncontrolled active-series key with two safety nets:
 *
 * 1. If the controlled key points at a series that has disappeared (filter,
 *    schema change, refresh) the hook pushes `null` back through
 *    `onActiveKeyChange` so sibling charts stop highlighting a stale key.
 * 2. The setter dedupes against a ref so per-pixel hover events don't keep
 *    firing the callback after `useState` already bailed out.
 *
 * Refs are synced during render so parent-driven external resets flow through
 * without a stale comparison.
 */
export declare const useLineChartActiveKey: ({ controlledActiveKey, onActiveKeyChange, seriesByKey, }: {
    controlledActiveKey: string | null | undefined;
    onActiveKeyChange: ((key: string | null) => void) | undefined;
    seriesByKey: Map<string, LineChartSeries>;
}) => UseLineChartActiveKeyResult;
export {};