From 610539d14f3d147e891024f534769389b15a737c Mon Sep 17 00:00:00 2001
From: Arunoda Susiripala <arunoda.susiripala@gmail.com>
Date: Thu, 23 Mar 2017 10:57:16 +0530
Subject: [PATCH 1/4] Use a webpack plugin to combine assets.

---
 package.json                                  |   1 +
 server/build/index.js                         |  22 ++-
 server/build/plugins/combine-assets-plugin.js |  24 +++
 server/build/webpack.js                       |   2 +
 server/document.js                            |  21 ++-
 server/index.js                               |   6 +
 yarn.lock                                     | 143 +++++++++++-------
 7 files changed, 151 insertions(+), 68 deletions(-)
 create mode 100644 server/build/plugins/combine-assets-plugin.js

diff --git a/package.json b/package.json
index 8cd7913402649..3123224d1a1db 100644
--- a/package.json
+++ b/package.json
@@ -67,6 +67,7 @@
     "is-windows-bash": "1.0.3",
     "json-loader": "0.5.4",
     "loader-utils": "1.1.0",
+    "md5-file": "3.1.1",
     "minimist": "1.2.0",
     "mitt": "1.1.0",
     "mkdirp-then": "1.2.0",
diff --git a/server/build/index.js b/server/build/index.js
index 0fcff294423b3..ca7cb7eb5b42d 100644
--- a/server/build/index.js
+++ b/server/build/index.js
@@ -5,14 +5,15 @@ import uuid from 'uuid'
 import del from 'del'
 import webpack from './webpack'
 import replaceCurrentBuild from './replace'
+import md5File from 'md5-file/promise'
 
 export default async function build (dir) {
   const buildDir = join(tmpdir(), uuid.v4())
   const compiler = await webpack(dir, { buildDir })
 
   try {
-    const webpackStats = await runCompiler(compiler)
-    await writeBuildStats(buildDir, webpackStats)
+    await runCompiler(compiler)
+    await writeBuildStats(buildDir)
     await writeBuildId(buildDir)
   } catch (err) {
     console.error(`> Failed to build on ${buildDir}`)
@@ -44,17 +45,14 @@ function runCompiler (compiler) {
   })
 }
 
-async function writeBuildStats (dir, webpackStats) {
-  const chunkHashMap = {}
-  webpackStats.chunks
-    // We are not interested about pages
-    .filter(({ files }) => !/^bundles/.test(files[0]))
-    .forEach(({ hash, files }) => {
-      chunkHashMap[files[0]] = { hash }
-    })
-
+async function writeBuildStats (dir) {
+  const assetHashMap = {
+    'app.js': {
+      hash: await md5File(join(dir, '.next', 'app.js'))
+    }
+  }
   const buildStatsPath = join(dir, '.next', 'build-stats.json')
-  await fs.writeFile(buildStatsPath, JSON.stringify(chunkHashMap), 'utf8')
+  await fs.writeFile(buildStatsPath, JSON.stringify(assetHashMap), 'utf8')
 }
 
 async function writeBuildId (dir) {
diff --git a/server/build/plugins/combine-assets-plugin.js b/server/build/plugins/combine-assets-plugin.js
new file mode 100644
index 0000000000000..e8f8559898e8a
--- /dev/null
+++ b/server/build/plugins/combine-assets-plugin.js
@@ -0,0 +1,24 @@
+export default class CombineAssetsPlugin {
+  apply (compiler) {
+    compiler.plugin('after-compile', (compilation, callback) => {
+      const input = [
+        'commons.js',
+        'main.js'
+      ]
+      const output = 'app.js'
+
+      let newSource = ''
+      input.forEach((name) => {
+        newSource += `${compilation.assets[name].source()}\n`
+        delete compilation.assets[name]
+      })
+
+      compilation.assets[output] = {
+        source: () => newSource,
+        size: () => newSource.length
+      }
+
+      callback()
+    })
+  }
+}
diff --git a/server/build/webpack.js b/server/build/webpack.js
index e4b0403db532f..16c9c084ca5ab 100644
--- a/server/build/webpack.js
+++ b/server/build/webpack.js
@@ -7,6 +7,7 @@ import FriendlyErrorsWebpackPlugin from 'friendly-errors-webpack-plugin'
 import CaseSensitivePathPlugin from 'case-sensitive-paths-webpack-plugin'
 import UnlinkFilePlugin from './plugins/unlink-file-plugin'
 import JsonPagesPlugin from './plugins/json-pages-plugin'
+import CombineAssetsPlugin from './plugins/combine-assets-plugin'
 import getConfig from '../config'
 import * as babelCore from 'babel-core'
 import findBabelConfig from './babel/find-config'
@@ -119,6 +120,7 @@ export default async function createCompiler (dir, { dev = false, quiet = false,
     }
   } else {
     plugins.push(
+      new CombineAssetsPlugin(),
       new webpack.optimize.UglifyJsPlugin({
         compress: { warnings: false },
         sourceMap: false
diff --git a/server/document.js b/server/document.js
index 5bd502afd909d..1d1d800521dc5 100644
--- a/server/document.js
+++ b/server/document.js
@@ -59,16 +59,30 @@ export class NextScript extends Component {
     _documentProps: PropTypes.any
   }
 
-  getChunkScript (filename) {
+  getChunkScript (filename, additionalProps = {}) {
     const { __NEXT_DATA__ } = this.context._documentProps
     let { buildStats } = __NEXT_DATA__
     const hash = buildStats ? buildStats[filename].hash : '-'
 
     return (
-      <script type='text/javascript' src={`/_next/${hash}/${filename}`} defer />
+      <script type='text/javascript' src={`/_next/${hash}/${filename}`} {...additionalProps} />
     )
   }
 
+  getScripts () {
+    const { dev } = this.context._documentProps
+    if (dev) {
+      return (
+        <div>
+          { this.getChunkScript('commons.js') }
+          { this.getChunkScript('main.js') }
+        </div>
+      )
+    }
+
+    return this.getChunkScript('app.js', { async: true })
+  }
+
   render () {
     const { staticMarkup, __NEXT_DATA__ } = this.context._documentProps
 
@@ -76,8 +90,7 @@ export class NextScript extends Component {
       {staticMarkup ? null : <script dangerouslySetInnerHTML={{
         __html: `__NEXT_DATA__ = ${htmlescape(__NEXT_DATA__)}; module={};`
       }} />}
-      { staticMarkup ? null : this.getChunkScript('commons.js') }
-      { staticMarkup ? null : this.getChunkScript('main.js') }
+      {staticMarkup ? null : this.getScripts()}
     </div>
   }
 }
diff --git a/server/index.js b/server/index.js
index f08a9fec8ed95..26c58ab5b2293 100644
--- a/server/index.js
+++ b/server/index.js
@@ -102,6 +102,12 @@ export default class Server {
         await this.serveStatic(req, res, p)
       },
 
+      '/_next/:hash/app.js': async (req, res, params) => {
+        this.handleBuildHash('app.js', params.hash, res)
+        const p = join(this.dir, '.next/app.js')
+        await this.serveStatic(req, res, p)
+      },
+
       '/_next/:buildId/pages/:path*': async (req, res, params) => {
         if (!this.handleBuildId(params.buildId, res)) {
           res.setHeader('Content-Type', 'application/json')
diff --git a/yarn.lock b/yarn.lock
index 498e858ec6cd3..386b18e2a91b4 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -455,13 +455,13 @@ babel-plugin-check-es2015-constants@^6.22.0:
   dependencies:
     babel-runtime "^6.22.0"
 
-babel-plugin-istanbul@4.0.0, babel-plugin-istanbul@^4.0.0:
-  version "4.0.0"
-  resolved "https://registry.npmjs.org/babel-plugin-istanbul/-/babel-plugin-istanbul-4.0.0.tgz#36bde8fbef4837e5ff0366531a2beabd7b1ffa10"
+babel-plugin-istanbul@4.1.1:
+  version "4.1.1"
+  resolved "https://registry.yarnpkg.com/babel-plugin-istanbul/-/babel-plugin-istanbul-4.1.1.tgz#c12de0fc6fe42adfb16be56f1ad11e4a9782eca9"
   dependencies:
     find-up "^2.1.0"
-    istanbul-lib-instrument "^1.4.2"
-    test-exclude "^4.0.0"
+    istanbul-lib-instrument "^1.6.2"
+    test-exclude "^4.0.3"
 
 babel-plugin-istanbul@^3.0.0:
   version "3.0.0"
@@ -472,6 +472,14 @@ babel-plugin-istanbul@^3.0.0:
     object-assign "^4.1.0"
     test-exclude "^3.2.2"
 
+babel-plugin-istanbul@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.npmjs.org/babel-plugin-istanbul/-/babel-plugin-istanbul-4.0.0.tgz#36bde8fbef4837e5ff0366531a2beabd7b1ffa10"
+  dependencies:
+    find-up "^2.1.0"
+    istanbul-lib-instrument "^1.4.2"
+    test-exclude "^4.0.0"
+
 babel-plugin-jest-hoist@^18.0.0:
   version "18.0.0"
   resolved "https://registry.npmjs.org/babel-plugin-jest-hoist/-/babel-plugin-jest-hoist-18.0.0.tgz#4150e70ecab560e6e7344adc849498072d34e12a"
@@ -1301,9 +1309,9 @@ concat-map@0.0.1:
   version "0.0.1"
   resolved "https://registry.npmjs.org/concat-map/-/concat-map-0.0.1.tgz#d8a96bd77fd68df7793a73036a3ba0d5405d477b"
 
-concat-stream@^1.4.6:
+concat-stream@^1.5.2:
   version "1.6.0"
-  resolved "https://registry.npmjs.org/concat-stream/-/concat-stream-1.6.0.tgz#0aac662fd52be78964d5532f694784e70110acf7"
+  resolved "https://registry.yarnpkg.com/concat-stream/-/concat-stream-1.6.0.tgz#0aac662fd52be78964d5532f694784e70110acf7"
   dependencies:
     inherits "^2.0.3"
     readable-stream "^2.2.2"
@@ -1581,6 +1589,13 @@ doctrine@^1.2.2:
     esutils "^2.0.2"
     isarray "^1.0.0"
 
+doctrine@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/doctrine/-/doctrine-2.0.0.tgz#c73d8d2909d22291e1a007a395804da8b665fe63"
+  dependencies:
+    esutils "^2.0.2"
+    isarray "^1.0.0"
+
 dom-serializer@0, dom-serializer@~0.1.0:
   version "0.1.0"
   resolved "https://registry.npmjs.org/dom-serializer/-/dom-serializer-0.1.0.tgz#073c697546ce0780ce23be4a28e293e40bc30c82"
@@ -1797,9 +1812,9 @@ eslint-config-standard-jsx@3.3.0:
   version "3.3.0"
   resolved "https://registry.npmjs.org/eslint-config-standard-jsx/-/eslint-config-standard-jsx-3.3.0.tgz#cab0801a15a360bf63facb97ab22fbdd88d8a5e0"
 
-eslint-config-standard@7.0.0:
-  version "7.0.0"
-  resolved "https://registry.npmjs.org/eslint-config-standard/-/eslint-config-standard-7.0.0.tgz#4f161bc65695e4bc61331c55b9eeaca458cd99c6"
+eslint-config-standard@7.1.0:
+  version "7.1.0"
+  resolved "https://registry.yarnpkg.com/eslint-config-standard/-/eslint-config-standard-7.1.0.tgz#47e769ea0739f5b2d5693b1a501c21c9650fafcf"
 
 eslint-plugin-promise@~3.4.0:
   version "3.4.2"
@@ -1817,17 +1832,18 @@ eslint-plugin-standard@~2.0.1:
   version "2.0.1"
   resolved "https://registry.npmjs.org/eslint-plugin-standard/-/eslint-plugin-standard-2.0.1.tgz#3589699ff9c917f2c25f76a916687f641c369ff3"
 
-eslint@~3.15.0:
-  version "3.15.0"
-  resolved "https://registry.npmjs.org/eslint/-/eslint-3.15.0.tgz#bdcc6a6c5ffe08160e7b93c066695362a91e30f2"
+eslint@~3.18.0:
+  version "3.18.0"
+  resolved "https://registry.yarnpkg.com/eslint/-/eslint-3.18.0.tgz#647e985c4ae71502d20ac62c109f66d5104c8a4b"
   dependencies:
     babel-code-frame "^6.16.0"
     chalk "^1.1.3"
-    concat-stream "^1.4.6"
+    concat-stream "^1.5.2"
     debug "^2.1.1"
-    doctrine "^1.2.2"
+    doctrine "^2.0.0"
     escope "^3.6.0"
     espree "^3.4.0"
+    esquery "^1.0.0"
     estraverse "^4.2.0"
     esutils "^2.0.2"
     file-entry-cache "^2.0.0"
@@ -1871,6 +1887,12 @@ esprima@^3.1.1:
   version "3.1.3"
   resolved "https://registry.npmjs.org/esprima/-/esprima-3.1.3.tgz#fdca51cee6133895e3c88d535ce49dbff62a4633"
 
+esquery@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/esquery/-/esquery-1.0.0.tgz#cfba8b57d7fba93f17298a8a006a04cda13d80fa"
+  dependencies:
+    estraverse "^4.0.0"
+
 esrecurse@^4.1.0:
   version "4.1.0"
   resolved "https://registry.npmjs.org/esrecurse/-/esrecurse-4.1.0.tgz#4713b6536adf7f2ac4f327d559e7756bff648220"
@@ -1882,7 +1904,7 @@ estraverse@^1.9.1:
   version "1.9.3"
   resolved "https://registry.npmjs.org/estraverse/-/estraverse-1.9.3.tgz#af67f2dc922582415950926091a4005d29c9bb44"
 
-estraverse@^4.1.1, estraverse@^4.2.0:
+estraverse@^4.0.0, estraverse@^4.1.1, estraverse@^4.2.0:
   version "4.2.0"
   resolved "https://registry.npmjs.org/estraverse/-/estraverse-4.2.0.tgz#0dee3fed31fcd469618ce7342099fc1afa0bdb13"
 
@@ -2730,6 +2752,18 @@ istanbul-lib-instrument@^1.1.1, istanbul-lib-instrument@^1.1.4, istanbul-lib-ins
     istanbul-lib-coverage "^1.0.0"
     semver "^5.3.0"
 
+istanbul-lib-instrument@^1.6.2:
+  version "1.6.2"
+  resolved "https://registry.yarnpkg.com/istanbul-lib-instrument/-/istanbul-lib-instrument-1.6.2.tgz#dac644f358f51efd6113536d7070959a0111f73b"
+  dependencies:
+    babel-generator "^6.18.0"
+    babel-template "^6.16.0"
+    babel-traverse "^6.18.0"
+    babel-types "^6.18.0"
+    babylon "^6.13.0"
+    istanbul-lib-coverage "^1.0.0"
+    semver "^5.3.0"
+
 istanbul-lib-report@^1.0.0-alpha.3:
   version "1.0.0-alpha.3"
   resolved "https://registry.npmjs.org/istanbul-lib-report/-/istanbul-lib-report-1.0.0-alpha.3.tgz#32d5f6ec7f33ca3a602209e278b2e6ff143498af"
@@ -3231,6 +3265,10 @@ makeerror@1.0.x:
   dependencies:
     tmpl "1.0.x"
 
+md5-file@3.1.1:
+  version "3.1.1"
+  resolved "https://registry.yarnpkg.com/md5-file/-/md5-file-3.1.1.tgz#db3c92c09bbda5c2de883fa5490dd711fddbbab9"
+
 md5-hex@^1.2.0:
   version "1.3.0"
   resolved "https://registry.npmjs.org/md5-hex/-/md5-hex-1.3.0.tgz#d2c4afe983c4370662179b8cad145219135046c4"
@@ -3425,7 +3463,7 @@ node-libs-browser@^2.0.0:
     util "^0.10.3"
     vm-browserify "0.0.4"
 
-node-notifier@5.1.2:
+node-notifier@5.1.2, node-notifier@^5.0.1:
   version "5.1.2"
   resolved "https://registry.npmjs.org/node-notifier/-/node-notifier-5.1.2.tgz#2fa9e12605fa10009d44549d6fcd8a63dde0e4ff"
   dependencies:
@@ -3434,15 +3472,6 @@ node-notifier@5.1.2:
     shellwords "^0.1.0"
     which "^1.2.12"
 
-node-notifier@^5.0.1:
-  version "5.0.2"
-  resolved "https://registry.npmjs.org/node-notifier/-/node-notifier-5.0.2.tgz#4438449fe69e321f941cef943986b0797032701b"
-  dependencies:
-    growly "^1.3.0"
-    semver "^5.3.0"
-    shellwords "^0.1.0"
-    which "^1.2.12"
-
 node-pre-gyp@^0.6.29:
   version "0.6.33"
   resolved "https://registry.npmjs.org/node-pre-gyp/-/node-pre-gyp-0.6.33.tgz#640ac55198f6a925972e0c16c4ac26a034d5ecc9"
@@ -3830,11 +3859,11 @@ public-encrypt@^4.0.0:
     parse-asn1 "^5.0.0"
     randombytes "^2.0.1"
 
-punycode@1.3.2, punycode@^1.2.4:
+punycode@1.3.2:
   version "1.3.2"
   resolved "https://registry.npmjs.org/punycode/-/punycode-1.3.2.tgz#9653a036fb7c1ee42342f2325cceefea3926c48d"
 
-punycode@^1.4.1:
+punycode@^1.2.4, punycode@^1.4.1:
   version "1.4.1"
   resolved "https://registry.npmjs.org/punycode/-/punycode-1.4.1.tgz#c0d5a63b2718800ad8e1eb0fa5269c84dd41845e"
 
@@ -4258,13 +4287,13 @@ sntp@1.x.x:
   dependencies:
     hoek "2.x.x"
 
-source-list-map@~0.1.7:
-  version "0.1.8"
-  resolved "https://registry.npmjs.org/source-list-map/-/source-list-map-0.1.8.tgz#c550b2ab5427f6b3f21f5afead88c4f5587b2106"
+source-list-map@^1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/source-list-map/-/source-list-map-1.0.1.tgz#cc1fc17122ae0a51978024c2cc0f8c35659026b8"
 
-source-map-support@0.4.13:
-  version "0.4.13"
-  resolved "https://registry.npmjs.org/source-map-support/-/source-map-support-0.4.13.tgz#9782e6f7deb424d5f173327a1879eb46453bdcd4"
+source-map-support@0.4.14:
+  version "0.4.14"
+  resolved "https://registry.yarnpkg.com/source-map-support/-/source-map-support-0.4.14.tgz#9d4463772598b86271b4f523f6c1f4e02a7d6aef"
   dependencies:
     source-map "^0.5.6"
 
@@ -4352,12 +4381,12 @@ standard-engine@~5.4.0:
     minimist "^1.1.0"
     pkg-conf "^2.0.0"
 
-standard@9.0.0:
-  version "9.0.0"
-  resolved "https://registry.npmjs.org/standard/-/standard-9.0.0.tgz#58b2acad4dc33823a7477568033c973fc5b6a995"
+standard@9.0.2:
+  version "9.0.2"
+  resolved "https://registry.yarnpkg.com/standard/-/standard-9.0.2.tgz#9bd3b9467492e212b1914d78553943ff9b48fd99"
   dependencies:
-    eslint "~3.15.0"
-    eslint-config-standard "7.0.0"
+    eslint "~3.18.0"
+    eslint-config-standard "7.1.0"
     eslint-config-standard-jsx "3.3.0"
     eslint-plugin-promise "~3.4.0"
     eslint-plugin-react "~6.9.0"
@@ -4530,6 +4559,16 @@ test-exclude@^4.0.0:
     read-pkg-up "^1.0.1"
     require-main-filename "^1.0.1"
 
+test-exclude@^4.0.3:
+  version "4.0.3"
+  resolved "https://registry.yarnpkg.com/test-exclude/-/test-exclude-4.0.3.tgz#86a13ce3effcc60e6c90403cf31a27a60ac6c4e7"
+  dependencies:
+    arrify "^1.0.1"
+    micromatch "^2.3.11"
+    object-assign "^4.1.0"
+    read-pkg-up "^1.0.1"
+    require-main-filename "^1.0.1"
+
 text-table@~0.2.0:
   version "0.2.0"
   resolved "https://registry.npmjs.org/text-table/-/text-table-0.2.0.tgz#7f5ee823ae805207c00af2df4a84ec3fcfa570b4"
@@ -4622,7 +4661,7 @@ ua-parser-js@^0.7.9:
   version "0.7.12"
   resolved "https://registry.npmjs.org/ua-parser-js/-/ua-parser-js-0.7.12.tgz#04c81a99bdd5dc52263ea29d24c6bf8d4818a4bb"
 
-uglify-js@^2.6, uglify-js@^2.7.5:
+uglify-js@^2.6, uglify-js@^2.8.5:
   version "2.8.7"
   resolved "https://registry.npmjs.org/uglify-js/-/uglify-js-2.8.7.tgz#e0391911507b6d2e05697a528f1686e90a11b160"
   dependencies:
@@ -4717,9 +4756,9 @@ watch@~0.10.0:
   version "0.10.0"
   resolved "https://registry.npmjs.org/watch/-/watch-0.10.0.tgz#77798b2da0f9910d595f1ace5b0c2258521f21dc"
 
-watchpack@^1.2.0:
+watchpack@^1.3.1:
   version "1.3.1"
-  resolved "https://registry.npmjs.org/watchpack/-/watchpack-1.3.1.tgz#7d8693907b28ce6013e7f3610aa2a1acf07dad87"
+  resolved "https://registry.yarnpkg.com/watchpack/-/watchpack-1.3.1.tgz#7d8693907b28ce6013e7f3610aa2a1acf07dad87"
   dependencies:
     async "^2.1.2"
     chokidar "^1.4.3"
@@ -4764,16 +4803,16 @@ webpack-hot-middleware@2.17.1:
     querystring "^0.2.0"
     strip-ansi "^3.0.0"
 
-webpack-sources@^0.1.4:
-  version "0.1.4"
-  resolved "https://registry.npmjs.org/webpack-sources/-/webpack-sources-0.1.4.tgz#ccc2c817e08e5fa393239412690bb481821393cd"
+webpack-sources@^0.2.0:
+  version "0.2.0"
+  resolved "https://registry.yarnpkg.com/webpack-sources/-/webpack-sources-0.2.0.tgz#fea93ba840f16cdd3f246f0ee95f88a9492c69fb"
   dependencies:
-    source-list-map "~0.1.7"
+    source-list-map "^1.0.1"
     source-map "~0.5.3"
 
-webpack@2.2.1:
-  version "2.2.1"
-  resolved "https://registry.npmjs.org/webpack/-/webpack-2.2.1.tgz#7bb1d72ae2087dd1a4af526afec15eed17dda475"
+webpack@2.3.1:
+  version "2.3.1"
+  resolved "https://registry.yarnpkg.com/webpack/-/webpack-2.3.1.tgz#55bce8baffe7c1f9dc3029adc048643b448318a8"
   dependencies:
     acorn "^4.0.4"
     acorn-dynamic-import "^2.0.0"
@@ -4791,9 +4830,9 @@ webpack@2.2.1:
     source-map "^0.5.3"
     supports-color "^3.1.0"
     tapable "~0.2.5"
-    uglify-js "^2.7.5"
-    watchpack "^1.2.0"
-    webpack-sources "^0.1.4"
+    uglify-js "^2.8.5"
+    watchpack "^1.3.1"
+    webpack-sources "^0.2.0"
     yargs "^6.0.0"
 
 whatwg-encoding@^1.0.1:

From 914c7fb926c50540605d95e3d41e1fa89fcb7029 Mon Sep 17 00:00:00 2001
From: Arunoda Susiripala <arunoda.susiripala@gmail.com>
Date: Thu, 23 Mar 2017 11:08:42 +0530
Subject: [PATCH 2/4] Add comments and make this releseable.

---
 server/build/index.js                         |  4 ++++
 server/build/plugins/combine-assets-plugin.js | 18 ++++++++++--------
 server/build/webpack.js                       |  5 ++++-
 server/document.js                            |  2 ++
 4 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/server/build/index.js b/server/build/index.js
index ca7cb7eb5b42d..9205d52cccdc0 100644
--- a/server/build/index.js
+++ b/server/build/index.js
@@ -46,6 +46,10 @@ function runCompiler (compiler) {
 }
 
 async function writeBuildStats (dir) {
+  // Here we can't use the hash in chunks.
+  // That's because app.js has no related chunk.
+  // It's created with merging the few assets. (commons.js and main.js)
+  // So, we need to generate the hash ourself.
   const assetHashMap = {
     'app.js': {
       hash: await md5File(join(dir, '.next', 'app.js'))
diff --git a/server/build/plugins/combine-assets-plugin.js b/server/build/plugins/combine-assets-plugin.js
index e8f8559898e8a..2a1bd1e75735b 100644
--- a/server/build/plugins/combine-assets-plugin.js
+++ b/server/build/plugins/combine-assets-plugin.js
@@ -1,19 +1,21 @@
+// This pulgin merge a set of assets into a single asset
+// This should be only used with text assets,
+// otherwise the result is unpredictable.
 export default class CombineAssetsPlugin {
+  constructor ({ input, output }) {
+    this.input = input
+    this.output = output
+  }
+
   apply (compiler) {
     compiler.plugin('after-compile', (compilation, callback) => {
-      const input = [
-        'commons.js',
-        'main.js'
-      ]
-      const output = 'app.js'
-
       let newSource = ''
-      input.forEach((name) => {
+      this.input.forEach((name) => {
         newSource += `${compilation.assets[name].source()}\n`
         delete compilation.assets[name]
       })
 
-      compilation.assets[output] = {
+      compilation.assets[this.output] = {
         source: () => newSource,
         size: () => newSource.length
       }
diff --git a/server/build/webpack.js b/server/build/webpack.js
index 16c9c084ca5ab..0aff98de76cce 100644
--- a/server/build/webpack.js
+++ b/server/build/webpack.js
@@ -120,7 +120,10 @@ export default async function createCompiler (dir, { dev = false, quiet = false,
     }
   } else {
     plugins.push(
-      new CombineAssetsPlugin(),
+      new CombineAssetsPlugin({
+        input: ['commons.js', 'main.js'],
+        output: 'app.js'
+      }),
       new webpack.optimize.UglifyJsPlugin({
         compress: { warnings: false },
         sourceMap: false
diff --git a/server/document.js b/server/document.js
index 1d1d800521dc5..7b1eb160a7654 100644
--- a/server/document.js
+++ b/server/document.js
@@ -80,6 +80,8 @@ export class NextScript extends Component {
       )
     }
 
+    // In the production mode, we have a single asset
+    // So, we can load the script with async
     return this.getChunkScript('app.js', { async: true })
   }
 

From 408d6ac76edbc86f2c48491565f351364b6c7c15 Mon Sep 17 00:00:00 2001
From: Arunoda Susiripala <arunoda.susiripala@gmail.com>
Date: Thu, 23 Mar 2017 11:13:23 +0530
Subject: [PATCH 3/4] Fix some typos.

---
 server/build/index.js                         | 4 ++--
 server/build/plugins/combine-assets-plugin.js | 2 +-
 server/document.js                            | 8 ++++++--
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/server/build/index.js b/server/build/index.js
index 9205d52cccdc0..93bb2fa7af6e1 100644
--- a/server/build/index.js
+++ b/server/build/index.js
@@ -46,8 +46,8 @@ function runCompiler (compiler) {
 }
 
 async function writeBuildStats (dir) {
-  // Here we can't use the hash in chunks.
-  // That's because app.js has no related chunk.
+  // Here we can't use the hashes in the webpack chunks.
+  // That's because the "app.js" is not tight with a chunk.
   // It's created with merging the few assets. (commons.js and main.js)
   // So, we need to generate the hash ourself.
   const assetHashMap = {
diff --git a/server/build/plugins/combine-assets-plugin.js b/server/build/plugins/combine-assets-plugin.js
index 2a1bd1e75735b..759e0dce9686a 100644
--- a/server/build/plugins/combine-assets-plugin.js
+++ b/server/build/plugins/combine-assets-plugin.js
@@ -1,4 +1,4 @@
-// This pulgin merge a set of assets into a single asset
+// This pulgin combines a set of assets into a single asset
 // This should be only used with text assets,
 // otherwise the result is unpredictable.
 export default class CombineAssetsPlugin {
diff --git a/server/document.js b/server/document.js
index 7b1eb160a7654..d169cfe44af54 100644
--- a/server/document.js
+++ b/server/document.js
@@ -65,7 +65,11 @@ export class NextScript extends Component {
     const hash = buildStats ? buildStats[filename].hash : '-'
 
     return (
-      <script type='text/javascript' src={`/_next/${hash}/${filename}`} {...additionalProps} />
+      <script
+        type='text/javascript'
+        src={`/_next/${hash}/${filename}`}
+        {...additionalProps}
+      />
     )
   }
 
@@ -80,7 +84,7 @@ export class NextScript extends Component {
       )
     }
 
-    // In the production mode, we have a single asset
+    // In the production mode, we have a single asset with all the JS content.
     // So, we can load the script with async
     return this.getChunkScript('app.js', { async: true })
   }

From a9a0595664b18d56b6d3fc5d31cfc493f380b2a7 Mon Sep 17 00:00:00 2001
From: Arunoda Susiripala <arunoda.susiripala@gmail.com>
Date: Fri, 24 Mar 2017 13:15:25 +0530
Subject: [PATCH 4/4] Fix some typos.

---
 server/build/index.js                         | 6 +++---
 server/build/plugins/combine-assets-plugin.js | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/server/build/index.js b/server/build/index.js
index 93bb2fa7af6e1..e13d36ff66f98 100644
--- a/server/build/index.js
+++ b/server/build/index.js
@@ -46,9 +46,9 @@ function runCompiler (compiler) {
 }
 
 async function writeBuildStats (dir) {
-  // Here we can't use the hashes in the webpack chunks.
-  // That's because the "app.js" is not tight with a chunk.
-  // It's created with merging the few assets. (commons.js and main.js)
+  // Here we can't use hashes in webpack chunks.
+  // That's because the "app.js" is not tied to a chunk.
+  // It's created by merging a few assets. (commons.js and main.js)
   // So, we need to generate the hash ourself.
   const assetHashMap = {
     'app.js': {
diff --git a/server/build/plugins/combine-assets-plugin.js b/server/build/plugins/combine-assets-plugin.js
index 759e0dce9686a..959c14cdfc164 100644
--- a/server/build/plugins/combine-assets-plugin.js
+++ b/server/build/plugins/combine-assets-plugin.js
@@ -1,4 +1,4 @@
-// This pulgin combines a set of assets into a single asset
+// This plugin combines a set of assets into a single asset
 // This should be only used with text assets,
 // otherwise the result is unpredictable.
 export default class CombineAssetsPlugin {