chore(database): return emtpy fields when attributes not specified (#2034)

* test: append nested field

* chore: return emtpy fields when attributes not specified

* fix: test

* fix: data template error

---------

Co-authored-by: chenos <chenlinxh@gmail.com>

packages/core/database/src/__tests__/field-options/sort-by.test.ts

@@ -151,10 +151,11 @@ describe('associated field order', () => {
     });
 
     const u1 = await db.getRepository('users').findOne({
-      appends: ['posts.tags'],
+      appends: ['posts.tags', 'posts.title'],
     });
 
     const u1Json = u1.toJSON();
+
     const u1Posts = u1Json['posts'];
     expect(u1Posts.map((p) => p['title'])).toEqual(['a', 'b', 'c']);
 

packages/core/database/src/__tests__/repository/find.test.ts

@@ -488,6 +488,17 @@ describe('repository find', () => {
       expect(user['posts']).toBeDefined();
     });
 
+    test('find with nested fields', async () => {
+      const user = await User.repository.findOne({
+        fields: ['posts.comments.content'],
+      });
+
+      const userData = user.toJSON();
+
+      const post = userData['posts'][0];
+      expect(Object.keys(post)).toEqual(['comments']);
+    });
+
     describe('find with appends', () => {
       test('toJSON', async () => {
         const user = await User.repository.findOne({

packages/core/database/src/eager-loading/eager-loading-tree.ts

@@ -343,7 +343,8 @@ export class EagerLoadingTree {
         });
       }
 
-      const nodeRawAttributes = node.rawAttributes;
+      // if no attributes are specified, return empty fields
+      const nodeRawAttributes = node.rawAttributes || [];
 
       if (!lodash.isArray(nodeRawAttributes)) {
         return;

packages/core/server/src/middlewares/data-template.ts

@@ -37,7 +37,7 @@ const traverseBelongsToMany = (arr: any[], { collection, exclude = [], through }
   const throughCollection = collection.db.getCollection(through);
   return arr.map((item) => {
     const data = traverseJSON(item[through], { collection: throughCollection, exclude });
-    if (Object.keys(data).length) {
+    if (data && Object.keys(data).length) {
       item[through] = data;
     } else {
       delete item[through];