avoid "undefined" as classname

jdeniau · jdeniau · commit 10085fb2c9ad · 2021-12-13T15:20:58.000+01:00
diff --git a/website/src/MarkdownContent.tsx b/website/src/MarkdownContent.tsx
@@ -23,7 +23,7 @@ export const MarkdownContent = memo<Props>(function MarkdownContent({
 
   return (
     <div
-      className={'markdown ' + className}
+      className={'markdown ' + (className || '')}
       onClick={handleClick}
       dangerouslySetInnerHTML={{ __html: contents }}
     />
