diff --git a/HISTORY.md b/HISTORY.md
index 7228684..f39d711 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,3 +1,8 @@
+Unreleased changes
+==================
+
+  * improve toClassName function readability and JSDoc completeness
+
 2.0.0 / 2021-12-17
 ==================
 
diff --git a/index.js b/index.js
index c425f1e..82271f6 100644
--- a/index.js
+++ b/index.js
@@ -279,11 +279,12 @@ function populateConstructorExports (exports, codes, HttpError) {
 
 /**
  * Get a class name from a name identifier.
+ *
+ * @param {string} name
+ * @returns {string}
  * @private
  */
 
 function toClassName (name) {
-  return name.substr(-5) !== 'Error'
-    ? name + 'Error'
-    : name
+  return name.slice(-5) === 'Error' ? name : name + 'Error'
 }