fix(v2): Fix babel-loader not transpiling docusaurus package (#1661)

packages/docusaurus/CHANGELOG.md

@@ -1,5 +1,8 @@
 # Docusaurus 2 Changelog
 
+## 2.0.0-alpha.21
+- Fix babel-loader not transpiling docusaurus package
+
 ## 2.0.0-alpha.20
 
 - Added Google analytics and Google gtag plugins.

packages/docusaurus/src/webpack/base.ts

@@ -125,8 +125,12 @@ export function createBaseConfig(
       rules: [
         {
           test: /\.jsx?$/,
-          include: [siteDir, /docusaurus/],
-          exclude: /node_modules/,
+          exclude: modulePath => {
+            // Don't transpile node_modules except any docusaurus package
+            return (
+              /node_modules/.test(modulePath) && !/docusaurus/.test(modulePath)
+            );
+          },
           use: [
             cacheLoader && getCacheLoader(isServer),
             getBabelLoader(isServer),