Fix react-hot-loader error by providing module id

Author: jeremija

inc/index.js

@@ -553,7 +553,7 @@ function main(
 
       initModule: function(name, module) {
         // Set module.id for react-hot-loader support.
-        module.id = name;
+        module.id = moduleMeta[name] ? moduleMeta[name].index : name;
 
         runtimeModuleInfo[name].module = module;
         module.hot = {

index.js

@@ -227,7 +227,13 @@ module.exports = function(bundle, opts) {
   }
 
   function fileKey(filename) {
-    return path.relative(basedir, filename);
+    const relative = path.relative(basedir, filename);
+    if (/^[a-zA-Z0-9]/.test(relative)) {
+      // Example: return ./Label.jsx instead of Label.jsx - reverse module id
+      // lookup would not work with just Label.jsx
+      return './' + relative
+    }
+    return relative
   }
 
   var hmrManagerFilename;