Make sure pages bundles are served correctly

lib/page-loader.js

-/* global window, document, __NEXT_DATA__ */
+/* global window, document */
 import EventEmitter from './EventEmitter'
 
 const webpackModule = module
@@ -69,11 +69,7 @@ export default class PageLoader {
 
   loadScript (route) {
     route = this.normalizeRoute(route)
-    let scriptRoute = route
-
-    if (__NEXT_DATA__.nextExport) {
-      scriptRoute = route === '/' ? '/index.js' : `${route}.js`
-    }
+    const scriptRoute = route === '/' ? '/index.js' : `${route}.js`
 
     const script = document.createElement('script')
     const url = `${this.assetPrefix}/_next/${encodeURIComponent(this.buildId)}/page${scriptRoute}`

server/index.js

@@ -194,12 +194,12 @@ export default class Server {
         await this.serveStatic(req, res, p)
       },
 
-      '/_next/:buildId/page/:path*': async (req, res, params) => {
+      '/_next/:buildId/page/:path*.js': async (req, res, params) => {
         const paths = params.path || ['']
         // URL is asks for ${page}.js (to support loading assets from static dirs)
         // But there's no .js in the actual page.
         // So, we need to remove .js to get the page name.
-        const page = `/${paths.join('/')}`.replace('.js', '')
+        const page = `/${paths.join('/')}`
 
         if (!this.handleBuildId(params.buildId, res)) {
           const error = new Error('INVALID_BUILD_ID')
@@ -222,8 +222,11 @@ export default class Server {
           }
         }
 
-        const p = join(this.dir, this.dist, 'bundles', 'pages', paths.join('/'))
-        await this.serveStatic(req, res, p)
+        let p = join(this.dir, this.dist, 'bundles', 'pages', paths.join('/'))
+        if (!fs.existsSync(`${p}.js`)) {
+          p = join(p, 'index') // It's possible to have index.js in a subfolder
+        }
+        await this.serveStatic(req, res, `${p}.js`)
       },
 
       // It's very important keep this route's param optional.