Function useVirtualTree

app/hooks/useVirtualTree.ts:205–606

(
  options: UseVirtualTreeOptions<T, R>
)

}

export function useVirtualTree<T extends { id: string; children?: T[] }, R>(
  options: UseVirtualTreeOptions<T, R>
): UseVirtualTreeInstance<T> {
  const reducer = useCallback<Reducer<TreeState<T>, TreeAction>>(
    (state, action) => {
      switch (action.type) {
        case "BLUR": {
          return {
            ...state,
            focusedNodeId: null,
          };
        }
        case "TOGGLE_NODE": {
          const isCollapsed = state.collapsedState[action.id];

          if (isCollapsed) {
            return expandNode<T>(state, action.id);
          } else {
            if (
              action.source &&
              (action.source.shiftKey || action.source.altKey)
            ) {
              return toggleAllChildren<T>(state, action.id);
            } else {
              return collapseNode<T>(state, action.id);
            }
          }
        }
        case "COLLAPSE_ALL_NODES": {
          // Reduce from the right, so that the
          // focusedNodeId is set to the top-level node.
          return state.items.reduceRight(
            (nextState, item) => collapseNode<T>(nextState, item.id),
            state
          );
        }
        case "FOCUS_NODE": {
          const itemIndex = state.items.findIndex(({ id }) => id === action.id);

          if (itemIndex === -1) {
            const node = findNodeInTreeById(state.nodes, action.id);

            if (!node) {
              return state;
            }

            const path = calculatePathToNode(state.nodes, node) ?? [];

            const collapsedState = path.reduce(
              (acc, id) => ({
                ...acc,
                [id]: false,
              }),
              state.collapsedState
            );

            return {
              ...state,