Add support for webpack's CommonsChunkPlugin and remove next bundle (#301)

* Add example app which demonstrate the problem.

* Add the first working version.

* Fix lint issues.

* Add README.md

* Use /_next/main.js as the main file URI

* Add the support for loading the core next bundle.

* Optimize the output by removing Next modules from pages.

* Use the same package.json as master use.

* Change the example repo's README for simpler instructions.

* Change example projects package.json to support next build and start.

* Change main.js into commons.js.

* Add support for hot core reload and errors.

* Introduce require based on eval-script.

* Add error reporting support with hot reloading.

* Update README.md

client/next-dev.js

@@ -1,6 +1,6 @@
 import 'react-hot-loader/patch'
 import * as next from './next'
-
-module.exports = next
+import { requireModule } from '../lib/eval-script'
 
 window.next = next
+module.exports = requireModule

client/next.js

@@ -4,24 +4,33 @@ import HeadManager from './head-manager'
 import { rehydrate } from '../lib/css'
 import Router from '../lib/router'
 import App from '../lib/app'
-import evalScript from '../lib/eval-script'
+import evalScript, { requireModule } from '../lib/eval-script'
 
 const {
   __NEXT_DATA__: { component, errorComponent, props, ids, err }
 } = window
 
-const Component = evalScript(component).default
-const ErrorComponent = evalScript(errorComponent).default
+document.addEventListener('DOMContentLoaded', () => {
+  const Component = evalScript(component).default
+  const ErrorComponent = evalScript(errorComponent).default
 
-export const router = new Router(window.location.href, {
-  Component,
-  ErrorComponent,
-  ctx: { err }
+  const router = new Router(window.location.href, {
+    Component,
+    ErrorComponent,
+    ctx: { err }
+  })
+
+  // This it to support error handling in the dev time with hot code reload.
+  if (window.next) {
+    window.next.router = router
+  }
+
+  const headManager = new HeadManager()
+  const container = document.getElementById('__next')
+  const appProps = { Component, props, router, headManager }
+
+  rehydrate(ids)
+  render(createElement(App, appProps), container)
 })
 
-const headManager = new HeadManager()
-const container = document.getElementById('__next')
-const appProps = { Component, props, router, headManager }
-
-rehydrate(ids)
-render(createElement(App, appProps), container)
+module.exports = requireModule

examples/shared-modules/README.md

@@ -0,0 +1,13 @@
+# Example app using shared modules
+
+This example features:
+
+* An app with two pages which has a common Counter component
+* That Counter component maintain the counter inside its module.
+
+## How to run it
+
+```sh
+npm install
+npm run dev
+```

examples/shared-modules/components/Counter.js

@@ -0,0 +1,19 @@
+import React from 'react'
+
+let count = 0
+
+export default class Counter extends React.Component {
+  add () {
+    count += 1
+    this.forceUpdate()
+  }
+
+  render () {
+    return (
+      <div>
+        <p>Count is: {count}</p>
+        <button onClick={() => this.add()}>Add</button>
+      </div>
+    )
+  }
+}

examples/shared-modules/components/Header.js

@@ -0,0 +1,20 @@
+import React from 'react'
+import Link from 'next/link'
+
+const styles = {
+  a: {
+    marginRight: 10
+  }
+}
+
+export default () => (
+  <div>
+    <Link href='/'>
+      <a style={styles.a} >Home</a>
+    </Link>
+
+    <Link href='/about'>
+      <a style={styles.a} >About</a>
+    </Link>
+  </div>
+)

examples/shared-modules/package.json

@@ -0,0 +1,19 @@
+{
+  "name": "shared-modules",
+  "version": "1.0.0",
+  "description": "This example features:",
+  "main": "index.js",
+  "scripts": {
+    "dev": "next",
+    "build": "next build",
+    "start": "next start"
+  },
+  "dependencies": {
+    "next": "*"
+  },
+  "author": "",
+  "license": "ISC",
+  "next": {
+    "cdn": false
+  }
+}

examples/shared-modules/pages/about.js

@@ -0,0 +1,11 @@
+import React from 'react'
+import Header from '../components/Header'
+import Counter from '../components/Counter'
+
+export default () => (
+  <div>
+    <Header />
+    <p>This is the about page.</p>
+    <Counter />
+  </div>
+)

examples/shared-modules/pages/index.js

@@ -0,0 +1,11 @@
+import React from 'react'
+import Header from '../components/Header'
+import Counter from '../components/Counter'
+
+export default () => (
+  <div>
+    <Header />
+    <p>HOME PAGE is here!</p>
+    <Counter />
+  </div>
+)

gulpfile.js

@@ -100,7 +100,7 @@ gulp.task('build-dev-client', ['compile-lib', 'compile-client'], () => {
   .src('dist/client/next-dev.js')
   .pipe(webpack({
     quiet: true,
-    output: { filename: 'next-dev.bundle.js' },
+    output: { filename: 'next-dev.bundle.js', libraryTarget: 'var', library: 'require' },
     module: {
       loaders: [
         {
@@ -125,7 +125,7 @@ gulp.task('build-client', ['compile-lib', 'compile-client'], () => {
   .src('dist/client/next.js')
   .pipe(webpack({
     quiet: true,
-    output: { filename: 'next.bundle.js' },
+    output: { filename: 'next.bundle.js', libraryTarget: 'var', library: 'require' },
     plugins: [
       new webpack.webpack.DefinePlugin({
         'process.env': {

lib/document.js

@@ -10,8 +10,11 @@ export default ({ head, css, html, data, dev, staticMarkup, cdn }) => {
     </head>
     <body>
       <div id='__next' dangerouslySetInnerHTML={{ __html: html }} />
-      {staticMarkup ? null : <script dangerouslySetInnerHTML={{ __html: '__NEXT_DATA__ = ' + htmlescape(data) }} />}
+      {staticMarkup ? null : <script dangerouslySetInnerHTML={{
+        __html: `__NEXT_DATA__ =${htmlescape(data)}; module={};`
+      }} />}
       {staticMarkup ? null : createClientScript({ dev, cdn })}
+      <script type='text/javascript' src='/_next/commons.js' />
     </body>
   </html>
 }
@@ -30,7 +33,6 @@ function createClientScript ({ dev, cdn }) {
       load('https://cdn.zeit.co/next.js/${pkg.version}/next.min.js', function (err) {
         if (err) load('/_next/next.bundle.js')
       })
-
       function load (src, fn) {
         fn = fn || function () {}
         var script = document.createElement('script')

lib/eval-script.js

@@ -14,6 +14,17 @@ const modules = new Map([
   ['next/head', Head]
 ])
 
+function require (moduleName) {
+  const name = moduleName
+  const m = modules.get(name)
+
+  if (m) return m
+
+  throw new Error(`Module "${moduleName}" is not exists in the bundle`)
+}
+
+export const requireModule = require
+
 /**
  * IMPORTANT: This module is compiled *without* `use strict`
  * so that when we `eval` a dependency below, we don't enforce
@@ -28,10 +39,6 @@ const modules = new Map([
 
 export default function evalScript (script) {
   const module = { exports: {} }
-  const require = function (path) { // eslint-disable-line no-unused-vars
-    return modules.get(path)
-  }
-  // don't use Function() here since it changes source locations
   eval(script) // eslint-disable-line no-eval
   return module.exports
 }

server/build/webpack.js

@@ -39,6 +39,10 @@ export default async function createCompiler (dir, { hotReload = false, dev = fa
       log: false,
       // required not to cache removed files
       useHashIndex: false
+    }),
+    new webpack.optimize.CommonsChunkPlugin({
+      name: 'commons',
+      filename: 'commons.js'
     })
   ]
 

server/index.js

@@ -40,6 +40,11 @@ export default class Server {
   }
 
   defineRoutes () {
+    this.router.get('/_next/commons.js', async (req, res, params) => {
+      const p = join(this.dir, '.next/commons.js')
+      await this.serveStatic(req, res, p)
+    })
+
     this.router.get('/_next/:path+', async (req, res, params) => {
       const p = join(__dirname, '..', 'client', ...(params.path || []))
       await this.serveStatic(req, res, p)