diff --git a/src/services/MarkdownRenderer.ts b/src/services/MarkdownRenderer.ts
index 4b51381f15..491ed37432 100644
--- a/src/services/MarkdownRenderer.ts
+++ b/src/services/MarkdownRenderer.ts
@@ -98,7 +98,10 @@ export class MarkdownRenderer {
           `<a class="share-link" href="#${id}"></a>`
         );
       } else if (tokens[idx].hLevel === 2) {
-        const { id } = this.saveHeading(content, this.currentTopHeading.items);
+        const { id } = this.saveHeading(
+          content,
+          this.currentTopHeading && this.currentTopHeading.items,
+        );
         return (
           `<a name="${id}"></a>` +
           `<h${tokens[idx].hLevel} ${SECTION_ATTR}="${id}" id="${id}">` +