Disallow empty comments and comments with only whitespaces (#7156)

* fix: disallow empty comments

* fix: avoid full traversal to validate comment

* fix: text

* fix:review

* fix: review

shared/editor/nodes/Image.tsx

@@ -166,6 +166,8 @@ export default class Image extends SimpleImage {
           ["p", { class: "caption" }, 0],
         ];
       },
+      toPlainText: (node) =>
+        node.attrs.alt ? `(image: ${node.attrs.alt})` : "(image)",
     };
   }
 

shared/utils/ProsemirrorHelper.ts

@@ -142,8 +142,35 @@ export class ProsemirrorHelper {
    *
    * @returns True if the editor is empty
    */
-  static isEmpty(doc: Node) {
-    return !doc || doc.textContent.trim() === "";
+  static isEmpty(doc: Node, schema?: Schema) {
+    if (!schema) {
+      return !doc || doc.textContent.trim() === "";
+    }
+
+    const textSerializers = Object.fromEntries(
+      Object.entries(schema.nodes)
+        .filter(([, node]) => node.spec.toPlainText)
+        .map(([name, node]) => [name, node.spec.toPlainText])
+    );
+
+    let empty = true;
+    doc.descendants((child: Node) => {
+      // If we've already found non-empty data, we can stop descending further
+      if (!empty) {
+        return false;
+      }
+
+      const toPlainText = textSerializers[child.type.name];
+      if (toPlainText) {
+        empty = !toPlainText(child).trim();
+      } else if (child.isText) {
+        empty = !child.text?.trim();
+      }
+
+      return empty;
+    });
+
+    return empty;
   }
 
   /**