@mui/x-tree-view/esm/hooks/useApplyPropagationToSelectedItemsOnMount.js

The community edition of the MUI X Tree View components.

import { useRefWithInit } from '@base-ui/utils/useRefWithInit';
import { getLookupFromArray } from "../internals/plugins/selection/TreeViewSelectionPlugin.js";
const defaultGetItemId = item => item.id;
const defaultGetItemChildren = item => item.children;

/**
 * Applies the selection propagation rules to the selected items.
 * The value is only computed during the first render, any update of the parameters will be ignored.
 *
 * Uncontrolled example:
 * ```tsx
 * const defaultSelectedItems = useApplyPropagationToSelectedItemsOnMount({
 *   items: props.items,
 *   selectionPropagation: props.selectionPropagation,
 *   selectedItems: ['10', '11', '13', '14'],
 * });
 *
 * return (
 *   <RichTreeView
 *     items={props.items}
 *     selectionPropagation={props.selectionPropagation}
 *     defaultSelectedItems={defaultSelectedItems}
 *   />
 * );
 * ```
 *
 * Controlled example:
 * ```tsx
 * const initialSelectedItems = useApplyPropagationToSelectedItemsOnMount({
 *   items: props.items,
 *   selectionPropagation: props.selectionPropagation,
 *   selectedItems: ['10', '11', '13', '14'],
 * });
 *
 * const [selectedItems, setSelectedItems] = React.useState(initialSelectedItems);
 *
 * return (
 *   <RichTreeView
 *     items={props.items}
 *     selectionPropagation={props.selectionPropagation}
 *     selectedItems={selectedItems}
 *     onSelectedItemsChange={setSelectedItems}
 *   />
 * );
 * ```
 */
export function useApplyPropagationToSelectedItemsOnMount(parameters) {
  const {
    items: itemsParam,
    getItemId = defaultGetItemId,
    getItemChildren = defaultGetItemChildren,
    selectedItems,
    selectionPropagation
  } = parameters;
  return useRefWithInit(() => {
    const lookup = getLookupFromArray(selectedItems);
    function walk(items, isParentSelected) {
      for (const item of items) {
        const itemId = getItemId(item);
        let isSelected = lookup[itemId];
        if (!isSelected && selectionPropagation.descendants && isParentSelected) {
          lookup[itemId] = true;
          isSelected = true;
        }
        const children = getItemChildren(item) ?? [];
        if (children.length > 0) {
          walk(children, isSelected);
          if (!isSelected && selectionPropagation.parents) {
            const areAllChildrenSelected = children.every(childId => lookup[getItemId(childId)]);
            if (areAllChildrenSelected) {
              lookup[itemId] = true;
            }
          }
        }
      }
    }
    walk(itemsParam, false);
    return Object.keys(lookup);
  }).current;
}