diff --git a/base64.js b/base64.js
index db641dc..374fb36 100644
--- a/base64.js
+++ b/base64.js
@@ -42,8 +42,8 @@
      * @deprecated use lowercase `version`.
      */
     var VERSION = version;
-    var _hasatob = typeof atob === 'function';
-    var _hasbtoa = typeof btoa === 'function';
+    var typeof atob === 'function' = typeof atob === 'function';
+    var typeof btoa === 'function' = typeof btoa === 'function';
     var _hasBuffer = typeof Buffer === 'function';
     var _TD = typeof TextDecoder === 'function' ? new TextDecoder() : undefined;
     var _TE = typeof TextEncoder === 'function' ? new TextEncoder() : undefined;
@@ -87,7 +87,7 @@
      * @param {String} bin binary string
      * @returns {string} Base64-encoded string
      */
-    var _btoa = _hasbtoa ? function (bin) { return btoa(bin); }
+    var _btoa = typeof btoa === 'function' ? function (bin) { return btoa(bin); }
         : _hasBuffer ? function (bin) { return Buffer.from(bin, 'binary').toString('base64'); }
             : btoaPolyfill;
     var _fromUint8Array = _hasBuffer
@@ -216,7 +216,7 @@
      * @param {String} asc Base64-encoded string
      * @returns {string} binary string
      */
-    var _atob = _hasatob ? function (asc) { return atob(_tidyB64(asc)); }
+    var _atob = typeof atob === 'function' ? function (asc) { return atob(_tidyB64(asc)); }
         : _hasBuffer ? function (asc) { return Buffer.from(asc, 'base64').toString('binary'); }
             : atobPolyfill;
     //
diff --git a/base64.mjs b/base64.mjs
index 1569e63..40225a2 100644
--- a/base64.mjs
+++ b/base64.mjs
@@ -14,8 +14,6 @@ const version = '3.7.6';
  * @deprecated use lowercase `version`.
  */
 const VERSION = version;
-const _hasatob = typeof atob === 'function';
-const _hasbtoa = typeof btoa === 'function';
 const _hasBuffer = typeof Buffer === 'function';
 const _TD = typeof TextDecoder === 'function' ? new TextDecoder() : undefined;
 const _TE = typeof TextEncoder === 'function' ? new TextEncoder() : undefined;
@@ -59,7 +57,7 @@ const btoaPolyfill = (bin) => {
  * @param {String} bin binary string
  * @returns {string} Base64-encoded string
  */
-const _btoa = _hasbtoa ? (bin) => btoa(bin)
+const _btoa = typeof btoa === 'function' ? (bin) => btoa(bin)
     : _hasBuffer ? (bin) => Buffer.from(bin, 'binary').toString('base64')
         : btoaPolyfill;
 const _fromUint8Array = _hasBuffer
@@ -182,7 +180,7 @@ const atobPolyfill = (asc) => {
  * @param {String} asc Base64-encoded string
  * @returns {string} binary string
  */
-const _atob = _hasatob ? (asc) => atob(_tidyB64(asc))
+const _atob = typeof atob === 'function' ? (asc) => atob(_tidyB64(asc))
     : _hasBuffer ? (asc) => Buffer.from(asc, 'base64').toString('binary')
         : atobPolyfill;
 //
diff --git a/base64.ts b/base64.ts
index acfd107..87bc3c0 100644
--- a/base64.ts
+++ b/base64.ts
@@ -14,8 +14,6 @@ const version = '3.7.6';
  * @deprecated use lowercase `version`.
  */
 const VERSION = version;
-const _hasatob = typeof atob === 'function';
-const _hasbtoa = typeof btoa === 'function';
 const _hasBuffer = typeof Buffer === 'function';
 const _TD = typeof TextDecoder === 'function' ? new TextDecoder() : undefined;
 const _TE = typeof TextEncoder === 'function' ? new TextEncoder() : undefined;
@@ -61,7 +59,7 @@ const btoaPolyfill = (bin: string) => {
  * @param {String} bin binary string
  * @returns {string} Base64-encoded string
  */
-const _btoa = _hasbtoa ? (bin: string) => btoa(bin)
+const _btoa = typeof btoa === 'function' ? (bin: string) => btoa(bin)
     : _hasBuffer ? (bin: string) => Buffer.from(bin, 'binary').toString('base64')
         : btoaPolyfill;
 const _fromUint8Array = _hasBuffer
@@ -188,7 +186,7 @@ const atobPolyfill = (asc: string) => {
  * @param {String} asc Base64-encoded string
  * @returns {string} binary string
  */
-const _atob = _hasatob ? (asc: string) => atob(_tidyB64(asc))
+const _atob = typeof atob === 'function' ? (asc: string) => atob(_tidyB64(asc))
     : _hasBuffer ? (asc: string) => Buffer.from(asc, 'base64').toString('binary')
         : atobPolyfill;
 //