make sure content is string for post-processing

src/services/notes.js

@@ -889,6 +889,10 @@ function scanForLinks(note, content) {
  * Things which have to be executed after updating content, but asynchronously (separate transaction)
  */
 async function asyncPostProcessContent(note, content) {
+    if (note.hasStringContent() && !utils.isString(content)) {
+        content = content.toString();
+    }
+
     scanForLinks(note, content);
 }
 

src/services/utils.js

@@ -303,6 +303,10 @@ function toMap(list, key) {
     return map;
 }
 
+function isString(x) {
+    return Object.prototype.toString.call(x) === "[object String]";
+}
+
 module.exports = {
     randomSecureToken,
     randomString,
@@ -335,4 +339,5 @@ module.exports = {
     normalize,
     hashedBlobId,
     toMap,
+    isString
 };