@mui/x-tree-view/internals/plugins/expansion/selectors.mjs

The community edition of the MUI X Tree View components.

import { createSelectorMemoized } from '@mui/x-internals/store';
import { itemsSelectors } from "../items/selectors.mjs";
import { TREE_VIEW_ROOT_PARENT_ID } from "../items/index.mjs";
const expandedItemMapSelector = createSelectorMemoized(state => state.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: state => state.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: state => state.expansionTrigger,
  /**
   * Checks whether an item is expanded.
   */
  isItemExpanded: (state, itemId) => expandedItemMapSelector(state).has(itemId),
  /**
   * Checks whether an item is expandable.
   */
  isItemExpandable: (state, itemId) => itemsSelectors.itemMeta(state, itemId)?.expandable ?? false
};