Move webpack idle wait code to the page-loader.

Because that's the place to do it.

lib/page-loader.js

@@ -1,6 +1,8 @@
 /* global window, document */
 import mitt from 'mitt'
 
+const webpackModule = module
+
 export default class PageLoader {
   constructor (buildId) {
     this.buildId = buildId
@@ -18,19 +20,6 @@ export default class PageLoader {
     return route.replace(/index$/, '')
   }
 
-  loadPageSync (route) {
-    route = this.normalizeRoute(route)
-    const cachedPage = this.pageCache[route]
-
-    if (!cachedPage) {
-      return null
-    } else if (cachedPage.error) {
-      throw cachedPage.error
-    } else {
-      return cachedPage.page
-    }
-  }
-
   loadPage (route) {
     route = this.normalizeRoute(route)
 
@@ -79,12 +68,32 @@ export default class PageLoader {
   }
 
   // This method if called by the route code.
-  registerPage (route, error, page) {
-    route = this.normalizeRoute(route)
+  registerPage (route, regFn) {
+    const register = () => {
+      regFn((error, page) => {
+        route = this.normalizeRoute(route)
 
-    // add the page to the cache
-    this.pageCache[route] = { error, page }
-    this.registerEvents.emit(route, { error, page })
+        // add the page to the cache
+        this.pageCache[route] = { error, page }
+        this.registerEvents.emit(route, { error, page })
+      })
+    }
+
+    // Wait for webpack to became idle if it's not.
+    // More info: https://github.com/zeit/next.js/pull/1511
+    if (webpackModule && webpackModule.hot && webpackModule.hot.status() !== 'idle') {
+      console.log(`Waiting webpack to became "idle" to initialize the page: "${route}"`)
+
+      const check = (status) => {
+        if (status === 'idle') {
+          webpackModule.hot.removeStatusHandler(check)
+          register()
+        }
+      }
+      webpackModule.hot.status(check)
+    } else {
+      register()
+    }
   }
 
   clearCache (route) {

lib/router/router.js

@@ -5,8 +5,6 @@ import PQueue from '../p-queue'
 import { loadGetInitialProps, getURL } from '../utils'
 import { _notifyBuildIdMismatch } from './'
 
-const webpackModule = module
-
 export default class Router {
   constructor (pathname, query, as, { pageLoader, Component, ErrorComponent, err } = {}) {
     // represents the current component key
@@ -320,20 +318,6 @@ export default class Router {
   }
 
   async fetchRoute (route) {
-    // Wait for webpack to became idle if it's not.
-    // More info: https://github.com/zeit/next.js/pull/1511
-    if (webpackModule && webpackModule.hot && webpackModule.hot.status() !== 'idle') {
-      await new Promise((resolve) => {
-        const check = (status) => {
-          if (status === 'idle') {
-            webpackModule.hot.removeStatusHandler(check)
-            resolve()
-          }
-        }
-        webpackModule.hot.status(check)
-      })
-    }
-
     return await this.pageLoader.loadPage(route)
   }
 

server/build/plugins/pages-plugin.js

@@ -17,8 +17,10 @@ export default class PagesPlugin {
         const content = page.source()
         const newContent = `
           function loadPage () {
-            var comp = ${content}
-            window.__NEXT_PAGE_LOADER__.registerPage('${routeName}', null, comp.default)
+            window.__NEXT_PAGE_LOADER__.registerPage('${routeName}', function(cb) {
+              var comp = ${content}
+              cb(null, comp.default)
+            })
           }
 
           if (window.__NEXT_PAGE_LOADER__) {

server/render.js

@@ -123,7 +123,9 @@ export async function renderScriptError (req, res, page, error, customFields, op
         var error = new Error('Page not exists: ${page}')
         error.pageNotFound = true
         error.statusCode = 404
-        __NEXT_PAGE_LOADER__.registerPage('${page}', error)
+        __NEXT_PAGE_LOADER__.registerPage('${page}', function(cb) {
+          cb(error)
+        })
       }
       
       if (window.__NEXT_PAGE_LOADER__) {
@@ -145,7 +147,9 @@ export async function renderScriptError (req, res, page, error, customFields, op
   res.end(`
     function loadPage () {
       var error = ${JSON.stringify(errorJson)}
-      __NEXT_PAGE_LOADER__.registerPage('${page}', error)
+      __NEXT_PAGE_LOADER__.registerPage('${page}', function(cb) {
+        cb(error)
+      })
     }
     
     if (window.__NEXT_PAGE_LOADER__) {