Update loader/index.js

Co-authored-by: Michael Mok <pmmmwh@gmail.com>

Author: Timeless0911

loader/index.js

@@ -46,7 +46,7 @@ function ReactRefreshLoader(source, inputSourceMap, meta) {
 
   // When available, use `__webpack_global__` which is a stable runtime function to use `__webpack_require__` in this compilation
   // See: https://github.com/webpack/webpack/issues/20139
-  const RefreshGlobals = `(typeof __webpack_global__ === 'function' ? __webpack_global__ : __webpack_require__)`;
+  const RefreshGlobals = `(typeof __webpack_global__ !== 'undefined' ? __webpack_global__ : __webpack_require__)`;
 
   const RefreshSetupRuntimes = {
     cjs: Template.asString(