import { AppSharedState } from '../state.models';
import { ActionMapLayerAddFeatureKey } from '../state.models.actions';
/**
 * Reducer to add a featureKey to the selection for a vector layer in a map's rendering layers.
 * Ensures that in state.selections there is an object with the same key as the renderingLayer (selectionKey).
 * If not, it creates it. Assigns the lowest unused color index to the new featureKey.
 *
 * @param {AppSharedState} state - The current application state.
 * @param {ActionMapLayerAddFeatureKey} action - The action containing mapKey, layerKey, featureKey, and optional customSelectionStyle.
 * @returns {AppSharedState} - The updated application state with the featureKey added to the selection.
 * @throws {Error} If the payload is missing or the map/layer is not found.
 */
export declare const reduceHandlerAddFeatureKeyToSelections: <T extends AppSharedState = AppSharedState>(state: T, action: ActionMapLayerAddFeatureKey) => T;