diff --git a/lib/zlib.js b/lib/zlib.js
index d5228e28e9a89a..4cc45a7c26d8b2 100644
--- a/lib/zlib.js
+++ b/lib/zlib.js
@@ -37,6 +37,7 @@ const {
   ObjectKeys,
   ObjectSetPrototypeOf,
   ReflectApply,
+  StringPrototypeStartsWith,
   Symbol,
   TypedArrayPrototypeFill,
   Uint32Array,
@@ -781,7 +782,9 @@ function createConvenienceMethod(ctor, sync) {
 
 const kMaxBrotliParam = MathMax(...ArrayPrototypeMap(
   ObjectKeys(constants),
-  (key) => (key.startsWith('BROTLI_PARAM_') ? constants[key] : 0)
+  (key) => (StringPrototypeStartsWith(key, 'BROTLI_PARAM_') ?
+    constants[key] :
+    0)
 ));
 
 const brotliInitParamsArray = new Uint32Array(kMaxBrotliParam + 1);
@@ -922,7 +925,7 @@ ObjectDefineProperties(module.exports, {
 // These should be considered deprecated
 // expose all the zlib constants
 for (const bkey of ObjectKeys(constants)) {
-  if (bkey.startsWith('BROTLI')) continue;
+  if (StringPrototypeStartsWith(bkey, 'BROTLI')) continue;
   ObjectDefineProperty(module.exports, bkey, {
     enumerable: false, value: constants[bkey], writable: false
   });