refactor(next-client-pages-loader): allow toggling router HMR

packages/next/build/entries.ts

@@ -61,6 +61,7 @@ type Entrypoints = {
 }
 
 export function createEntrypoints(
+  dev: boolean,
   pages: PagesMapping,
   target: 'server' | 'serverless' | 'experimental-serverless-trace',
   buildId: string,
@@ -132,6 +133,7 @@ export function createEntrypoints(
       const pageLoaderOpts: ClientPagesLoaderOptions = {
         page,
         absolutePagePath,
+        hotRouterUpdates: dev, // Hot router updates only apply in development mode
       }
       const pageLoader = `next-client-pages-loader?${stringify(
         pageLoaderOpts

packages/next/build/index.ts

@@ -217,6 +217,7 @@ export default async function build(dir: string, conf = null): Promise<void> {
 
   const mappedPages = createPagesMapping(pagePaths, config.pageExtensions)
   const entrypoints = createEntrypoints(
+    /* dev */ false,
     mappedPages,
     target,
     buildId,

packages/next/build/webpack/loaders/next-client-pages-loader.ts

@@ -4,25 +4,31 @@ import loaderUtils from 'loader-utils'
 export type ClientPagesLoaderOptions = {
   absolutePagePath: string
   page: string
+  hotRouterUpdates: boolean
 }
 
 const nextClientPagesLoader: loader.Loader = function() {
-  const { absolutePagePath, page }: any = loaderUtils.getOptions(this)
+  const { absolutePagePath, page, hotRouterUpdates } = loaderUtils.getOptions(
+    this
+  ) as ClientPagesLoaderOptions
   const stringifiedAbsolutePagePath = JSON.stringify(absolutePagePath)
   const stringifiedPage = JSON.stringify(page)
 
   return `
-    (window.__NEXT_P=window.__NEXT_P||[]).push([${stringifiedPage}, function() {
-      var mod = require(${stringifiedAbsolutePagePath})
-      if(module.hot) {
-        module.hot.accept(${stringifiedAbsolutePagePath}, function() {
-          if(!next.router.components[${stringifiedPage}]) return
-          var updatedPage = require(${stringifiedAbsolutePagePath})
-          next.router.update(${stringifiedPage}, updatedPage)
-        })
+    (window.__NEXT_P = window.__NEXT_P || []).push([
+      ${stringifiedPage},
+      function () {
+        var mod = require(${stringifiedAbsolutePagePath});
+        if (${!!hotRouterUpdates} && module.hot) {
+          module.hot.accept(${stringifiedAbsolutePagePath}, function () {
+            if (!next.router.components[${stringifiedPage}]) return;
+            var updatedPage = require(${stringifiedAbsolutePagePath});
+            next.router.update(${stringifiedPage}, updatedPage);
+          });
+        }
+        return mod;
       }
-      return mod
-    }]);
+    ]);
   `
 }
 

packages/next/server/hot-reloader.ts

@@ -252,6 +252,7 @@ export default class HotReloader {
       this.config.pageExtensions
     )
     const entrypoints = createEntrypoints(
+      /* dev */ true,
       pages,
       'server',
       this.buildId,
@@ -488,6 +489,7 @@ export default class HotReloader {
         pagesDir: this.pagesDir,
         reload: this.reload.bind(this),
         pageExtensions: this.config.pageExtensions,
+        hotRouterUpdates: true,
         ...(this.config.onDemandEntries as {
           maxInactiveAge: number
           pagesBufferLength: number

packages/next/server/on-demand-entry-handler.ts

@@ -48,13 +48,15 @@ export default function onDemandEntryHandler(
     pageExtensions,
     maxInactiveAge,
     pagesBufferLength,
+    hotRouterUpdates,
   }: {
     buildId: string
     pagesDir: string
     reload: any
     pageExtensions: string[]
     maxInactiveAge: number
     pagesBufferLength: number
+    hotRouterUpdates: boolean
   }
 ) {
   const { compilers } = multiCompiler
@@ -88,6 +90,7 @@ export default function onDemandEntryHandler(
           const pageLoaderOpts: ClientPagesLoaderOptions = {
             page,
             absolutePagePath,
+            hotRouterUpdates,
           }
           return addEntry(compilation, compiler.context, name, [
             compiler.name === 'client'

test/integration/production-config/test/index.test.js

@@ -39,6 +39,18 @@ describe('Production Config Usage', () => {
     })
   })
 
+  describe('with generateBuildId', () => {
+    it('should add the custom buildid', async () => {
+      const browser = await webdriver(appPort, '/')
+      const text = await browser.elementByCss('#mounted').text()
+      expect(text).toMatch(/ComponentDidMount executed on client\./)
+
+      const html = await browser.elementByCss('html').getAttribute('innerHTML')
+      expect(html).toMatch('custom-buildid')
+      await browser.close()
+    })
+  })
+
   describe('env', () => {
     it('should fail with leading __ in env key', async () => {
       const result = await runNextCommand(['build', appDir], {
@@ -70,18 +82,6 @@ describe('Production Config Usage', () => {
       expect(result.stderr).not.toMatch(/The key "SOME__ENV__VAR" under/)
     })
   })
-
-  describe('with generateBuildId', () => {
-    it('should add the custom buildid', async () => {
-      const browser = await webdriver(appPort, '/')
-      const text = await browser.elementByCss('#mounted').text()
-      expect(text).toMatch(/ComponentDidMount executed on client\./)
-
-      const html = await browser.elementByCss('html').getAttribute('innerHTML')
-      expect(html).toMatch('custom-buildid')
-      await browser.close()
-    })
-  })
 })
 
 async function testBrowser() {