@mui/x-tree-view/esm/internals/plugins/useTreeViewExpansion/useTreeViewExpansion.selectors.js

The community edition of the MUI X Tree View components.

import { createSelector, createSelectorMemoized } from '@mui/x-internals/store';
import { itemsSelectors } from "../useTreeViewItems/useTreeViewItems.selectors.js";
import { TREE_VIEW_ROOT_PARENT_ID } from "../useTreeViewItems/index.js";
const expandedItemMapSelector = createSelectorMemoized(state => state.expansion.expandedItems, expandedItems => {
  const expandedItemsMap = new Map();
  expandedItems.forEach(id => {
    expandedItemsMap.set(id, true);
  });
  return expandedItemsMap;
});
export const expansionSelectors = {
  /**
   * Gets the expanded items as provided to the component.
   */
  expandedItemsRaw: createSelector(state => state.expansion.expandedItems),
  /**
   * Gets the expanded items as a Map.
   */
  expandedItemsMap: expandedItemMapSelector,
  /**
   * Gets the items to render as a flat list (the descendants of an expanded item are listed as siblings of the item).
   */
  flatList: createSelectorMemoized(itemsSelectors.itemOrderedChildrenIdsLookup, expandedItemMapSelector, (itemOrderedChildrenIds, expandedItemsMap) => {
    function appendChildren(itemId) {
      if (!expandedItemsMap.has(itemId)) {
        return [itemId];
      }
      const itemsWithDescendants = [itemId];
      const children = itemOrderedChildrenIds[itemId] || [];
      for (const childId of children) {
        itemsWithDescendants.push(...appendChildren(childId));
      }
      return itemsWithDescendants;
    }
    return (itemOrderedChildrenIds[TREE_VIEW_ROOT_PARENT_ID] ?? []).flatMap(appendChildren);
  }),
  /**
   * Gets the slot that triggers the item's expansion when clicked.
   */
  triggerSlot: createSelector(state => state.expansion.expansionTrigger),
  /**
   * Checks whether an item is expanded.
   */
  isItemExpanded: createSelector(expandedItemMapSelector, (expandedItemsMap, itemId) => expandedItemsMap.has(itemId)),
  /**
   * Checks whether an item is expandable.
   */
  isItemExpandable: createSelector(itemsSelectors.itemMeta, (itemMeta, _itemId) => itemMeta?.expandable ?? false)
};