Function createTreeStateStore

packages/core/src/runtime/localState.ts:483–539

()

/** Create a new tree state store instance. */
export function createTreeStateStore(): TreeStateStore {
  const table = new Map<string, TreeLocalState>();

  const store: TreeStateStore = Object.freeze({
    get: (id) => table.get(id) ?? DEFAULT_TREE_STATE,
    set: (id, patch) => {
      const prev = table.get(id) ?? DEFAULT_TREE_STATE;
      const next: TreeLocalState = Object.freeze({
        focusedKey: patch.focusedKey !== undefined ? patch.focusedKey : prev.focusedKey,
        loadingKeys:
          patch.loadingKeys !== undefined ? cloneReadonlySet(patch.loadingKeys) : prev.loadingKeys,
        scrollTop: patch.scrollTop !== undefined ? patch.scrollTop : prev.scrollTop,
        viewportHeight:
          patch.viewportHeight !== undefined ? patch.viewportHeight : prev.viewportHeight,
        flatCache: patch.flatCache !== undefined ? patch.flatCache : prev.flatCache,
        expandedSetRef:
          patch.expandedSetRef !== undefined ? patch.expandedSetRef : prev.expandedSetRef,
        expandedSet:
          patch.expandedSet !== undefined ? cloneReadonlySet(patch.expandedSet) : prev.expandedSet,
        prefixCache: patch.prefixCache !== undefined ? patch.prefixCache : prev.prefixCache,
      });
      table.set(id, next);
      return next;
    },
    delete: (id) => {
      table.delete(id);
    },
    keys: () => table.keys(),
    startLoading: (id, nodeKey) => {
      const prev = table.get(id) ?? DEFAULT_TREE_STATE;
      const newLoading = new Set(prev.loadingKeys);
      newLoading.add(nodeKey);
      const next: TreeLocalState = Object.freeze({
        ...prev,
        loadingKeys: cloneReadonlySet(newLoading),
      });
      table.set(id, next);
      return next;
    },
    finishLoading: (id, nodeKey) => {
      const prev = table.get(id) ?? DEFAULT_TREE_STATE;
      if (!prev.loadingKeys.has(nodeKey)) {
        return prev;
      }
      const newLoading = new Set(prev.loadingKeys);
      newLoading.delete(nodeKey);
      const next: TreeLocalState = Object.freeze({
        ...prev,
        loadingKeys: cloneReadonlySet(newLoading),
      });
      table.set(id, next);
      return next;
    },
  });

  return store;
}