diff --git a/tools/doc/html.js b/tools/doc/html.js
index 898118d42bf9da..730031471fcc04 100644
--- a/tools/doc/html.js
+++ b/tools/doc/html.js
@@ -466,7 +466,7 @@ function getId(text) {
   text = text.replace(/^_+|_+$/, '');
   text = text.replace(/^([^a-z])/, '_$1');
   if (idCounters.hasOwnProperty(text)) {
-    text += `_${(++idCounters[text])}`;
+    text += `_${++idCounters[text]}`;
   } else {
     idCounters[text] = 0;
   }