From c23046dc79b80c754602339845d8eeeb5becccce Mon Sep 17 00:00:00 2001
From: Tim Neutkens <tim@timneutkens.nl>
Date: Fri, 22 Dec 2017 10:25:35 +0100
Subject: [PATCH] Rewrite combine-asset-plugin using correct event (#3486)

* Speed up next build

* Remove comment

* Add comment

* Add comments
---
 package.json                                  |  4 ++--
 server/build/plugins/combine-assets-plugin.js | 15 ++++++---------
 2 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/package.json b/package.json
index 6f0e6cff..651a5e1d 100644
--- a/package.json
+++ b/package.json
@@ -104,7 +104,8 @@
     "webpack-dev-middleware": "1.12.0",
     "webpack-hot-middleware": "2.19.1",
     "write-file-webpack-plugin": "4.2.0",
-    "xss-filters": "1.2.7"
+    "xss-filters": "1.2.7",
+    "uglifyjs-webpack-plugin": "^1.1.1"    
   },
   "devDependencies": {
     "@taskr/babel": "1.1.0",
@@ -134,7 +135,6 @@
     "react-dom": "16.0.0",
     "standard": "9.0.2",
     "taskr": "1.1.0",
-    "uglifyjs-webpack-plugin": "^1.1.1",
     "wd": "1.4.1"
   },
   "peerDependencies": {
diff --git a/server/build/plugins/combine-assets-plugin.js b/server/build/plugins/combine-assets-plugin.js
index b7bae4a4..274ac788 100644
--- a/server/build/plugins/combine-assets-plugin.js
+++ b/server/build/plugins/combine-assets-plugin.js
@@ -11,26 +11,23 @@ export default class CombineAssetsPlugin {
 
   apply (compiler) {
     compiler.plugin('compilation', (compilation) => {
-      compilation.plugin('additional-chunk-assets', (chunks) => {
+      // This is triggered after uglify and other optimizers have ran.
+      compilation.plugin('after-optimize-chunk-assets', (chunks) => {
         const concat = new ConcatSource()
 
         this.input.forEach((name) => {
           const asset = compilation.assets[name]
           if (!asset) return
 
+          // We add each matched asset from this.input to a new bundle
           concat.add(asset)
 
-          // We keep existing assets since that helps when analyzing the bundle
+          // The original assets are kept because they show up when analyzing the bundle using webpack-bundle-analyzer
+          // See https://github.com/zeit/next.js/tree/canary/examples/with-webpack-bundle-analyzer
         })
 
-        compilation.additionalChunkAssets.push(this.output)
+        // Creates a new asset holding the concatted source
         compilation.assets[this.output] = concat
-
-        // Register the combined file as an output of the associated chunks
-        chunks.filter((chunk) => {
-          return chunk.files.reduce((prev, file) => prev || this.input.includes(file), false)
-        })
-        .forEach((chunk) => chunk.files.push(this.output))
       })
     })
   }