diff --git a/tools/doc/html.js b/tools/doc/html.js
index 462de24fd7be59..6729dbba186268 100644
--- a/tools/doc/html.js
+++ b/tools/doc/html.js
@@ -518,7 +518,7 @@ 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;
   }