fix: handle default values for fractionalIndex and index in LoroTreeNode (#792)

Author: Leeeon233

.changeset/yellow-cobras-build.md

@@ -0,0 +1,5 @@
+---
+"loro-crdt": patch
+---
+
+fix: handle default values for fractionalIndex and index in LoroTreeNode

crates/loro-wasm/src/lib.rs

@@ -4120,8 +4120,11 @@ impl LoroTreeNode {
         let node = TreeNodeWithChildren {
             id: self.id,
             parent: self.tree.get_node_parent(&self.id).unwrap(),
-            fractional_index: self.tree.get_position_by_tree_id(&self.id).unwrap(),
-            index: self.tree.get_index_by_tree_id(&self.id).unwrap(),
+            fractional_index: self
+                .tree
+                .get_position_by_tree_id(&self.id)
+                .unwrap_or_default(),
+            index: self.tree.get_index_by_tree_id(&self.id).unwrap_or(0),
             children: value,
         };
         LoroTree {

crates/loro-wasm/tests/basic.test.ts

@@ -1708,3 +1708,17 @@ it("update text after switching to a version", () => {
   newDoc.setDetachedEditing(true);
   newDoc.getText("text").update("123");
 });
+
+it("tree deleted node to json", () => {
+  const doc = new LoroDoc();
+  doc.setPeerId(1);
+  const tree = doc.getTree("tree");
+  const root = tree.createNode();
+  tree.delete(root.id);
+  doc.commit();
+  const node = tree.getNodes({ withDeleted: true })[0].toJSON();
+  expect(node.parent).toBe('2147483647@18446744073709551615');
+  // default value
+  expect(node.fractionalIndex).toBe('80');
+  expect(node.index).toBe(0);
+});