🐛(y-provider) keep the sub-docs block when converting documents

Author: MashdorDev

src/frontend/servers/y-provider/__tests__/convert.test.ts

@@ -1,3 +1,8 @@
+import {
+  BlockNoteSchema,
+  createBlockSpec,
+  defaultBlockSpecs,
+} from '@blocknote/core';
 import {
   CommentsExtension,
   DefaultThreadStoreAuth,
@@ -703,6 +708,57 @@ describe('Conversion Testing', () => {
     });
   });
 
+  test('POST /api/convert keeps the docChildren block in JSON and leaves no trace of it in HTML or Markdown', async () => {
+    const app = initApp();
+    // Written the way the frontend writes it, with its own docChildren spec,
+    // so the test fails if the server schema drops the block when reading
+    const frontendEditor = ServerBlockNoteEditor.create({
+      schema: BlockNoteSchema.create({
+        blockSpecs: {
+          ...defaultBlockSpecs,
+          docChildren: createBlockSpec(
+            { type: 'docChildren', propSchema: {}, content: 'none' },
+            { render: () => ({ dom: document.createElement('div') }) },
+          )(),
+        },
+      }),
+    });
+    const yDocument = frontendEditor.blocksToYDoc(
+      [
+        { type: 'paragraph' as const, content: 'Before' },
+        { type: 'docChildren' as const },
+        { type: 'paragraph' as const, content: 'After' },
+      ],
+      'document-store',
+    );
+    const yjsUpdate = Buffer.from(Y.encodeStateAsUpdate(yDocument));
+    const convert = (accept: string) =>
+      request(app)
+        .post('/api/convert')
+        .set('origin', origin)
+        .set('authorization', `Bearer ${apiKey}`)
+        .set('content-type', 'application/vnd.yjs.doc')
+        .set('accept', accept)
+        .send(yjsUpdate);
+
+    const jsonResponse = await convert('application/json');
+    expect(jsonResponse.status).toBe(200);
+    expect(
+      (jsonResponse.body as { type: string }[]).map((block) => block.type),
+    ).toContain('docChildren');
+
+    const htmlResponse = await convert('text/html');
+    expect(htmlResponse.status).toBe(200);
+    expect(htmlResponse.text).toContain('After');
+    expect(htmlResponse.text).not.toContain('\uFFFC');
+
+    const markdownResponse = await convert('text/markdown');
+    expect(markdownResponse.status).toBe(200);
+    expect(markdownResponse.text).toContain('Before');
+    expect(markdownResponse.text).toContain('After');
+    expect(markdownResponse.text).not.toContain('\uFFFC');
+  });
+
   test('POST /api/convert with invalid Yjs content returns 400', async () => {
     const destroySpy = vi.spyOn(Y.Doc.prototype, 'destroy');
     const app = initApp();

src/frontend/servers/y-provider/src/blockSpecs/DocChildren.ts

@@ -0,0 +1,26 @@
+import { createBlockSpec } from '@blocknote/core';
+
+// Must stay in sync with the frontend DocChildrenBlock
+// (custom-blocks/DocChildrenBlock.tsx).
+const docChildrenConfig = {
+  type: 'docChildren' as const,
+  propSchema: {},
+  content: 'none' as const,
+};
+
+// Lists the sub-docs of the doc, which the editor fetches when it renders the
+// block. Conversion only has the document, not its sub-docs, so the block
+// renders as an empty marker: it round-trips in JSON and leaves nothing in
+// HTML or Markdown.
+export const DocChildrenBlock = createBlockSpec(docChildrenConfig, {
+  render: () => {
+    const dom = document.createElement('div');
+    dom.setAttribute('data-content-type', 'docChildren');
+    return { dom };
+  },
+  toExternalHTML: () => {
+    const dom = document.createElement('div');
+    dom.setAttribute('data-content-type', 'docChildren');
+    return { dom };
+  },
+});

src/frontend/servers/y-provider/src/blockSpecs/index.ts

@@ -6,6 +6,7 @@ import {
 } from '@blocknote/core';
 
 import { CalloutBlock } from './Callout';
+import { DocChildrenBlock } from './DocChildren';
 import { InterlinkingLinkInline } from './InterlinkingLinkInline';
 import { PdfBlock } from './Pdf';
 import { UploadLoaderBlock } from './UploadLoader';
@@ -17,6 +18,7 @@ export const docsBlockNoteSchema = withPageBreak(
     blockSpecs: {
       ...defaultBlockSpecs,
       callout: CalloutBlock(),
+      docChildren: DocChildrenBlock(),
       pdf: PdfBlock(),
       uploadLoader: UploadLoaderBlock(),
     },