Add unsupported text

packages/mermaid/src/rendering-util/handle-markdown-text.spec.ts

@@ -242,3 +242,12 @@ test('markdownToHTML - Mixed formatting', () => {
   const output = markdownToHTML(input);
   expect(output).toEqual(expectedOutput);
 });
+
+test('markdownToHTML - Unsupported formatting', () => {
+  expect(
+    markdownToHTML(`Hello
+  - l1
+  - l2
+  - l3`)
+  ).toMatchInlineSnapshot('"<p>Hello</p>Unsupported markdown: list"');
+});

packages/mermaid/src/rendering-util/handle-markdown-text.ts

@@ -68,7 +68,7 @@ export function markdownToHTML(markdown: string): string {
     } else if (node.type === 'paragraph') {
       return `<p>${node.children.map(output).join('')}</p>`;
     }
-    return '';
+    return `Unsupported markdown: ${node.type}`;
   }
 
   return children.map(output).join('');