4-26 树rust-2

wolai-frontend/convex/_utils/documentTree.ts

@@ -3,6 +3,29 @@ export type ParentLinkedRow = {
   parent_id?: string | null;
 };
 
+export function buildParentById<T extends ParentLinkedRow>(rows: readonly T[]): Map<string, string | null> {
+  const map = new Map<string, string | null>();
+  for (const row of rows) {
+    map.set(row.id, row.parent_id ?? null);
+  }
+  return map;
+}
+
+export function isAncestorOf(
+  ancestorId: string,
+  nodeId: string,
+  parentById: Map<string, string | null>,
+): boolean {
+  let current: string | null | undefined = nodeId;
+  while (current) {
+    const parentId = parentById.get(current);
+    if (!parentId) return false;
+    if (parentId === ancestorId) return true;
+    current = parentId;
+  }
+  return false;
+}
+
 /**
  * 收集以 rootId 为根的整棵子树（包含根节点本身）。
  *
@@ -41,4 +64,3 @@ export function collectSubtree<T extends ParentLinkedRow>(rows: readonly T[], ro
 
   return result;
 }
-