feat: Use globalThis if available

Author: eps1lon

package.json

@@ -65,6 +65,9 @@
   },
   "eslintConfig": {
     "extends": "./node_modules/kcd-scripts/eslint.js",
+    "globals": {
+      "globalThis": "readonly"
+    },
     "rules": {
       "react/prop-types": "off",
       "react/no-adjacent-inline-elements": "off",

src/act-compat.js

@@ -4,6 +4,10 @@ const domAct = testUtils.act
 
 function getGlobalThis() {
   /* istanbul ignore else */
+  if (typeof globalThis !== 'undefined') {
+    return globalThis
+  }
+  /* istanbul ignore next */
   if (typeof self !== 'undefined') {
     return self
   }