diff --git a/.eslintrc b/.eslintrc
index e6dd07c..3ad659f 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -27,7 +27,8 @@
     "globals": {
         "DEBUG": true,
         "process": true,
-        "Buffer": true
+        "Buffer": true,
+        "globalThis": true,
     },
     "extends": "eslint:recommended",
     "parserOptions": {
diff --git a/src/SourceMap.js b/src/SourceMap.js
index e909671..a91b319 100644
--- a/src/SourceMap.js
+++ b/src/SourceMap.js
@@ -1,8 +1,8 @@
 import { encode } from '@jridgewell/sourcemap-codec';
 
 function getBtoa() {
-	if (typeof window !== 'undefined' && typeof window.btoa === 'function') {
-		return (str) => window.btoa(unescape(encodeURIComponent(str)));
+	if (typeof globalThis !== 'undefined' && typeof globalThis.btoa === 'function') {
+		return (str) => globalThis.btoa(unescape(encodeURIComponent(str)));
 	} else if (typeof Buffer === 'function') {
 		return (str) => Buffer.from(str, 'utf-8').toString('base64');
 	} else {