react-native-tree-multi-select/lib/typescript/src/hooks/useScrollToNode.d.ts

Super-fast, customizable tree view component for React Native with drag-and-drop reordering, multi-selection, and search filtering.

/**
 * useScrollToNode Hook
 *
 * Provides an imperative handle to scroll to a specified node within a tree view.
 * The scrolling action is orchestrated via a two-step "milestone" mechanism that ensures the target
 * node is both expanded in the tree and that the rendered list reflects this expansion before the scroll
 * is performed.
 *
 * The two key milestones tracked by the `expandAndScrollToNodeQueue` state are:
 * 1. EXPANDED: Indicates that the expansion logic for the target node has been initiated.
 * 2. RENDERED: Indicates that the list has re-rendered with the expanded node included.
 *
 * When the `scrollToNodeID` method is called:
 * - The scroll parameters (target node ID, animation preferences, view offset/position) are stored in a ref.
 * - The target node's expansion is triggered via the `expandNodes` helper.
 * - The `expandAndScrollToNodeQueue` state is updated to mark that expansion has begun.
 *
 * As the component re-renders (e.g., after the node expansion changes the rendered list):
 * - A useEffect monitors changes to the list, and once it detects the expansion has occurred,
 *   it updates the queue to include the RENDERED milestone.
 *
 * A layout effect then waits for both conditions to be met:
 * - The target node is confirmed to be in the expanded set.
 * - The `expandAndScrollToNodeQueue` exactly matches the expected milestones ([EXPANDED, RENDERED]).
 *
 * Once both conditions are satisfied:
 * - The index of the target node is determined within the latest flattened node list.
 * - The flash list is scrolled to that index.
 * - The queued scroll parameters and milestone queue are reset.
 *
 * This design ensures that the scroll action is performed only after the target node is fully present
 * in the UI, thus preventing issues with attempting to scroll to an element that does not exist yet.
 */
import { type Dispatch, type MutableRefObject, type RefObject, type SetStateAction } from "react";
import { type __FlattenedTreeNode__ } from "../types/treeView.types";
export interface ScrollToNodeParams<ID> {
    nodeId: ID;
    expandScrolledNode?: boolean;
    animated?: boolean;
    viewOffset?: number;
    viewPosition?: number;
}
export interface ScrollToNodeHandlerRef<ID> {
    scrollToNodeID: (params: ScrollToNodeParams<ID>) => void;
}
/**
 * Scroll a just-moved node into view with the `DropAutoScrollOptions` defaults
 * (animated, centered). Deferred a tick so the post-move expand/render settles
 * first. Shared by the interactive drop path and the programmatic `moveNode`.
 */
export declare function scrollMovedNodeIntoView<ID>(scrollToNodeHandlerRef: RefObject<ScrollToNodeHandlerRef<ID> | null>, nodeId: ID, options: boolean | {
    animated?: boolean;
    viewPosition?: number;
    viewOffset?: number;
} | undefined): void;
interface UseScrollToNodeParams<ID> {
    storeId: string;
    scrollToNodeHandlerRef: RefObject<ScrollToNodeHandlerRef<ID>>;
    flashListRef: MutableRefObject<any>;
    flattenedFilteredNodes: __FlattenedTreeNode__<ID>[];
    setInitialScrollIndex: Dispatch<SetStateAction<number>>;
    initialScrollNodeID: ID | undefined;
}
export declare function useScrollToNode<ID>(params: UseScrollToNodeParams<ID>): void;
export {};
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