fix: use TiptapTransformer to extract Y.Doc content for publish

The old extractFromYDoc relied on a Y.Map("tiptap-json") that the
editor never populated. Now uses @hocuspocus /transformer to properly
convert the Y.XmlFragment to ProseMirror JSON using the same
extensions as the server-side HTML renderer.

Made-with: Cursor

backend/package-lock.json

@@ -16,6 +16,7 @@
         "@citation-js/plugin-doi": "^0.7.21",
         "@hocuspocus/extension-database": "^3.4.4",
         "@hocuspocus/server": "^3.4.4",
+        "@hocuspocus/transformer": "^3.4.4",
         "@huggingface/hub": "^2.11.0",
         "@openrouter/ai-sdk-provider": "^2.5.1",
         "@tiptap/core": "^3.22.3",
@@ -689,6 +690,21 @@
         "yjs": "^13.6.8"
       }
     },
+    "node_modules/@hocuspocus/transformer": {
+      "version": "3.4.4",
+      "resolved": "https://registry.npmjs.org/@hocuspocus/transformer/-/transformer-3.4.4.tgz",
+      "integrity": "sha512-X0EJ863LV97YbL5m8WTt4NDSC6uHi6ZCq/teIH5aholdjdhdTmFrzMemdhha/ZqPUZyaKhOoAmZzwR55HZLPpQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@tiptap/starter-kit": "^3.0.1"
+      },
+      "peerDependencies": {
+        "@tiptap/core": "^3.0.1",
+        "@tiptap/pm": "^3.0.1",
+        "y-prosemirror": "^1.2.1",
+        "yjs": "^13.6.8"
+      }
+    },
     "node_modules/@huggingface/hub": {
       "version": "2.11.0",
       "resolved": "https://registry.npmjs.org/@huggingface/hub/-/hub-2.11.0.tgz",
@@ -3242,6 +3258,31 @@
         }
       }
     },
+    "node_modules/y-prosemirror": {
+      "version": "1.3.7",
+      "resolved": "https://registry.npmjs.org/y-prosemirror/-/y-prosemirror-1.3.7.tgz",
+      "integrity": "sha512-NpM99WSdD4Fx4if5xOMDpPtU3oAmTSjlzh5U4353ABbRHl1HtAFUx6HlebLZfyFxXN9jzKMDkVbcRjqOZVkYQg==",
+      "license": "MIT",
+      "peer": true,
+      "dependencies": {
+        "lib0": "^0.2.109"
+      },
+      "engines": {
+        "node": ">=16.0.0",
+        "npm": ">=8.0.0"
+      },
+      "funding": {
+        "type": "GitHub Sponsors ❤",
+        "url": "https://github.com/sponsors/dmonad"
+      },
+      "peerDependencies": {
+        "prosemirror-model": "^1.7.1",
+        "prosemirror-state": "^1.2.3",
+        "prosemirror-view": "^1.9.10",
+        "y-protocols": "^1.0.1",
+        "yjs": "^13.5.38"
+      }
+    },
     "node_modules/y-protocols": {
       "version": "1.0.7",
       "resolved": "https://registry.npmjs.org/y-protocols/-/y-protocols-1.0.7.tgz",

backend/package.json

@@ -17,6 +17,7 @@
     "@citation-js/plugin-doi": "^0.7.21",
     "@hocuspocus/extension-database": "^3.4.4",
     "@hocuspocus/server": "^3.4.4",
+    "@hocuspocus/transformer": "^3.4.4",
     "@huggingface/hub": "^2.11.0",
     "@openrouter/ai-sdk-provider": "^2.5.1",
     "@tiptap/core": "^3.22.3",

backend/src/publisher/index.ts

@@ -8,7 +8,9 @@ import { readFileSync, existsSync } from "fs";
 import { join, dirname } from "path";
 import { fileURLToPath } from "url";
 import * as Y from "yjs";
+import { TiptapTransformer } from "@hocuspocus/transformer";
 import { renderArticleHTML, type PublishMeta } from "./html-renderer.js";
+import { getServerExtensions } from "./extensions.js";
 import { isPdfEnabled, generatePdfAndThumbnail } from "./pdf-generator.js";
 import {
   isHfStorageEnabled,
@@ -46,34 +48,29 @@ function loadCSS(): { tokens: string; article: string } {
 
 /**
  * Extract TipTap JSON and frontmatter from a Yjs document.
+ * Uses @hocuspocus/transformer to convert the XmlFragment to ProseMirror JSON.
  */
 function extractFromYDoc(ydoc: Y.Doc): {
   json: Record<string, unknown>;
   frontmatter: Record<string, unknown>;
 } {
-  const fragment = ydoc.getXmlFragment("default");
-
-  // The Hocuspocus/TipTap collaboration stores the ProseMirror document
-  // inside a Y.XmlFragment. We need to extract it as JSON.
-  // For now, we'll try reading the JSON from the shared map if available.
   const metaMap = ydoc.getMap("frontmatter");
   const frontmatter: Record<string, unknown> = {};
-
   metaMap.forEach((value, key) => {
     frontmatter[key] = value;
   });
 
-  // TipTap JSON is stored as the XmlFragment's prosemirror representation
-  // We need to reconstruct it. The simplest approach: store the JSON
-  // in a shared type when the editor saves.
-  const jsonMap = ydoc.getMap("tiptap-json");
-  const stored = jsonMap.get("doc");
+  // Convert Y.XmlFragment → ProseMirror JSON using TipTap extensions
+  const extensions = getServerExtensions();
+  const json = TiptapTransformer
+    .extensions(extensions)
+    .fromYdoc(ydoc, "default");
 
-  if (stored && typeof stored === "object") {
-    return { json: stored as Record<string, unknown>, frontmatter };
+  if (json && typeof json === "object" && json.type === "doc") {
+    return { json, frontmatter };
   }
 
-  // Fallback: return empty doc
+  console.warn("[publish] TiptapTransformer returned unexpected format, using fallback");
   return {
     json: { type: "doc", content: [{ type: "paragraph" }] },
     frontmatter,