Fix expandable block anchor resolution (#2625)

Author: gregberge

.changeset/beige-falcons-enjoy.md

@@ -0,0 +1,5 @@
+---
+'gitbook': patch
+---
+
+Fix expandable block anchore resolution

packages/gitbook/src/lib/document.test.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'bun:test';
 
-import { isNodeEmpty } from './document';
+import { getBlockTitle, isNodeEmpty } from './document';
 
 describe('isNodeEmpty', () => {
     it('should return true for a document with an empty paragraph', () => {
@@ -54,3 +54,76 @@ describe('isNodeEmpty', () => {
         ).toEqual(false);
     });
 });
+
+describe('#getBlockTitle', () => {
+    it('should return the title of an expandable block', () => {
+        expect(
+            getBlockTitle({
+                object: 'block',
+                type: 'expandable',
+                isVoid: true,
+                data: {},
+                key: 'OX8znB9VmbgK',
+                fragments: [
+                    {
+                        object: 'fragment',
+                        nodes: [
+                            {
+                                object: 'block',
+                                type: 'paragraph',
+                                isVoid: false,
+                                data: {},
+                                nodes: [
+                                    {
+                                        object: 'text',
+                                        leaves: [
+                                            {
+                                                object: 'leaf',
+                                                text: 'Title of expandable block',
+                                                marks: [],
+                                            },
+                                        ],
+                                        key: '7sZdCBHTw6Si',
+                                    },
+                                ],
+                                key: 'msYtjdwNmiAB',
+                            },
+                        ],
+                        key: 'cNhmBygbrP8N',
+                        fragment: 'expandable-title',
+                        type: 'expandable-title',
+                    },
+                    {
+                        object: 'fragment',
+                        nodes: [
+                            {
+                                object: 'block',
+                                type: 'paragraph',
+                                isVoid: false,
+                                data: {},
+                                nodes: [
+                                    {
+                                        object: 'text',
+                                        leaves: [
+                                            {
+                                                object: 'leaf',
+                                                text: 'And content of the expandable',
+                                                marks: [],
+                                            },
+                                        ],
+                                        key: '0GEghVKyWRBt',
+                                    },
+                                ],
+                                key: '9iEwdHdZ5y0S',
+                            },
+                        ],
+                        key: 'newg71i9Ujjl',
+                        fragment: 'expandable-body',
+                        type: 'expandable-body',
+                    },
+                ],
+                meta: { id: 'expandable-block' },
+            }),
+        ).toEqual('Title of expandable block');
+    });
+});

packages/gitbook/src/lib/document.ts

@@ -154,7 +154,7 @@ export function isNodeEmpty(
 export function getBlockTitle(block: DocumentBlock): string {
     switch (block.type) {
         case 'expandable': {
-            const titleFragment = getNodeFragmentByType(block, 'title');
+            const titleFragment = getNodeFragmentByType(block, 'expandable-title');
             if (titleFragment) {
                 return getNodeText(titleFragment);
             }