fix: webpack-plugin - use RHL global variable, fixes #1251

Author: theKashey

src/webpack/webpackTagCommonJSExports.js

@@ -4,7 +4,11 @@
 (function register() {
   // eslint-disable-line no-extra-semi
   /* react-hot-loader/webpack */
-  const reactHotLoader = require('react-hot-loader').default;
+  var safe_require = function() {
+    return typeof require === 'undefined' ? undefined : require('react-hot-loader');
+  };
+
+  var reactHotLoader = (typeof reactHotLoaderGlobal !== 'undefined' ? reactHotLoaderGlobal : safe_require()).default;
 
   if (!reactHotLoader) {
     return;
@@ -13,6 +17,9 @@
   /* eslint-disable camelcase, no-undef */
   const webpackExports = typeof __webpack_exports__ !== 'undefined' ? __webpack_exports__ : exports;
   /* eslint-enable camelcase, no-undef */
+  if (!webpackExports) {
+    return;
+  }
 
   if (typeof webpackExports === 'function') {
     reactHotLoader.register(webpackExports, 'module.exports', __FILENAME__);