Enable source maps in webpack chunking + bundling process (#3793)

* Removed combine-assets-plugin, since its very broken

* Bundle everything into app.js on production build

* Clean up

* Removed app.js from server routes

* Renamed app.js -> main.js and removed commons from loading

* Remove commons and react CommonChunks

* Removed the commons route

* Killing the entire build-stats hack for app.js

* Removed unused md5-file package

package.json

@@ -83,7 +83,6 @@
     "http-status": "1.0.1",
     "json-loader": "0.5.7",
     "loader-utils": "1.1.0",
-    "md5-file": "3.2.3",
     "minimist": "1.2.0",
     "mkdirp-then": "1.2.0",
     "mv": "2.1.1",

server/build/index.js

@@ -5,7 +5,6 @@ import webpack from 'webpack'
 import getConfig from '../config'
 import {PHASE_PRODUCTION_BUILD} from '../../lib/constants'
 import getBaseWebpackConfig from './webpack'
-import md5File from 'md5-file/promise'
 
 export default async function build (dir, conf = null) {
   const config = getConfig(PHASE_PRODUCTION_BUILD, dir, conf)
@@ -26,7 +25,6 @@ export default async function build (dir, conf = null) {
 
     await runCompiler(configs)
 
-    await writeBuildStats(dir, config)
     await writeBuildId(dir, buildId, config)
   } catch (err) {
     console.error(`> Failed to build`)
@@ -54,20 +52,6 @@ function runCompiler (compiler) {
   })
 }
 
-async function writeBuildStats (dir, config) {
-  // 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': {
-      hash: await md5File(join(dir, config.distDir, 'app.js'))
-    }
-  }
-  const buildStatsPath = join(dir, config.distDir, 'build-stats.json')
-  await fs.writeFile(buildStatsPath, JSON.stringify(assetHashMap), 'utf8')
-}
-
 async function writeBuildId (dir, buildId, config) {
   const buildIdPath = join(dir, config.distDir, 'BUILD_ID')
   await fs.writeFile(buildIdPath, buildId, 'utf8')

server/build/plugins/combine-assets-plugin.js

@@ -1,33 +0,0 @@
-import { ConcatSource } from 'webpack-sources'
-
-// 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 {
-  constructor ({ input, output }) {
-    this.input = input
-    this.output = output
-  }
-
-  apply (compiler) {
-    compiler.plugin('compilation', (compilation) => {
-      // 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)
-          // 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
-        })
-
-        // Creates a new asset holding the concatted source
-        compilation.assets[this.output] = concat
-      })
-    })
-  }
-}

server/build/webpack.js

@@ -6,7 +6,6 @@ import CaseSensitivePathPlugin from 'case-sensitive-paths-webpack-plugin'
 import WriteFilePlugin from 'write-file-webpack-plugin'
 import FriendlyErrorsWebpackPlugin from 'friendly-errors-webpack-plugin'
 import {getPages} from './webpack/utils'
-import CombineAssetsPlugin from './plugins/combine-assets-plugin'
 import PagesPlugin from './plugins/pages-plugin'
 import NextJsSsrImportPlugin from './plugins/nextjs-ssr-import'
 import DynamicChunksPlugin from './plugins/dynamic-chunks-plugin'
@@ -248,53 +247,17 @@ export default async function getBaseWebpackConfig (dir, {dev = false, isServer
       new webpack.DefinePlugin({
         'process.env.NODE_ENV': JSON.stringify(dev ? 'development' : 'production')
       }),
-      !isServer && new CombineAssetsPlugin({
-        input: ['manifest.js', 'react.js', 'commons.js', 'main.js'],
-        output: 'app.js'
-      }),
       !dev && new webpack.optimize.ModuleConcatenationPlugin(),
       !isServer && new PagesPlugin(),
       !isServer && new DynamicChunksPlugin(),
       isServer && new NextJsSsrImportPlugin(),
-      !isServer && new webpack.optimize.CommonsChunkPlugin({
-        name: `commons`,
-        filename: `commons.js`,
+      // In dev mode, we don't move anything to the commons bundle.
+      // In production we move common modules into the existing main.js bundle
+      !dev && !isServer && new webpack.optimize.CommonsChunkPlugin({
+        name: 'main.js',
+        filename: 'main.js',
         minChunks (module, count) {
-          // We need to move react-dom explicitly into common chunks.
-          // Otherwise, if some other page or module uses it, it might
-          // included in that bundle too.
-          if (module.context && module.context.indexOf(`${sep}react${sep}`) >= 0) {
-            return true
-          }
-
-          if (module.context && module.context.indexOf(`${sep}react-dom${sep}`) >= 0) {
-            return true
-          }
-
-          // In the dev we use on-demand-entries.
-          // So, it makes no sense to use commonChunks based on the minChunks count.
-          // Instead, we move all the code in node_modules into each of the pages.
-          if (dev) {
-            return false
-          }
-
-          // If there are one or two pages, only move modules to common if they are
-          // used in all of the pages. Otherwise, move modules used in at-least
-          // 1/2 of the total pages into commons.
-          if (totalPages <= 2) {
-            return count >= totalPages
-          }
-          return count >= totalPages * 0.5
-        }
-      }),
-      !isServer && new webpack.optimize.CommonsChunkPlugin({
-        name: 'react',
-        filename: 'react.js',
-        minChunks (module, count) {
-          if (dev) {
-            return false
-          }
-
+          // react
           if (module.resource && module.resource.includes(`${sep}react-dom${sep}`) && count >= 0) {
             return true
           }
@@ -302,11 +265,21 @@ export default async function getBaseWebpackConfig (dir, {dev = false, isServer
           if (module.resource && module.resource.includes(`${sep}react${sep}`) && count >= 0) {
             return true
           }
+          // react end
 
-          return false
+          // commons
+          // If there are one or two pages, only move modules to common if they are
+          // used in all of the pages. Otherwise, move modules used in at-least
+          // 1/2 of the total pages into commons.
+          if (totalPages <= 2) {
+            return count >= totalPages
+          }
+          return count >= totalPages * 0.5
+          // commons end
         }
       }),
-      !isServer && new webpack.optimize.CommonsChunkPlugin({
+      // We use a manifest file in development to speed up HMR
+      dev && !isServer && new webpack.optimize.CommonsChunkPlugin({
         name: 'manifest',
         filename: 'manifest.js'
       })

server/document.js

@@ -40,8 +40,8 @@ export class Head extends Component {
 
   getChunkPreloadLink (filename) {
     const { __NEXT_DATA__ } = this.context._documentProps
-    let { buildStats, assetPrefix, buildId } = __NEXT_DATA__
-    const hash = buildStats ? buildStats[filename].hash : buildId
+    let { assetPrefix, buildId } = __NEXT_DATA__
+    const hash = buildId
 
     return (
       <link
@@ -58,14 +58,13 @@ export class Head extends Component {
     if (dev) {
       return [
         this.getChunkPreloadLink('manifest.js'),
-        this.getChunkPreloadLink('commons.js'),
         this.getChunkPreloadLink('main.js')
       ]
     }
 
     // In the production mode, we have a single asset with all the JS content.
     return [
-      this.getChunkPreloadLink('app.js')
+      this.getChunkPreloadLink('main.js')
     ]
   }
 
@@ -126,8 +125,8 @@ export class NextScript extends Component {
 
   getChunkScript (filename, additionalProps = {}) {
     const { __NEXT_DATA__ } = this.context._documentProps
-    let { buildStats, assetPrefix, buildId } = __NEXT_DATA__
-    const hash = buildStats ? buildStats[filename].hash : buildId
+    let { assetPrefix, buildId } = __NEXT_DATA__
+    const hash = buildId
 
     return (
       <script
@@ -143,14 +142,13 @@ export class NextScript extends Component {
     if (dev) {
       return [
         this.getChunkScript('manifest.js'),
-        this.getChunkScript('commons.js'),
         this.getChunkScript('main.js')
       ]
     }
 
     // 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 })]
+    return [this.getChunkScript('main.js', { async: true })]
   }
 
   getDynamicChunks () {

server/export.js

@@ -27,20 +27,12 @@ export default async function (dir, options, configuration) {
   }
 
   const buildId = readFileSync(join(nextDir, 'BUILD_ID'), 'utf8')
-  const buildStats = require(join(nextDir, 'build-stats.json'))
 
   // Initialize the output directory
   const outDir = options.outdir
   await del(join(outDir, '*'))
-  await mkdirp(join(outDir, '_next', buildStats['app.js'].hash))
   await mkdirp(join(outDir, '_next', buildId))
 
-  // Copy files
-  await cp(
-    join(nextDir, 'app.js'),
-    join(outDir, '_next', buildStats['app.js'].hash, 'app.js')
-  )
-
   // Copy static directory
   if (existsSync(join(dir, 'static'))) {
     log('  copying "static" directory')
@@ -51,6 +43,12 @@ export default async function (dir, options, configuration) {
     )
   }
 
+  // Copy main.js
+  await cp(
+    join(nextDir, 'main.js'),
+    join(outDir, '_next', buildId, 'main.js')
+  )
+
   // Copy .next/static directory
   if (existsSync(join(nextDir, 'static'))) {
     log('  copying "static build" directory')
@@ -88,7 +86,6 @@ export default async function (dir, options, configuration) {
   const renderOpts = {
     dir,
     dist: nextConfig.distDir,
-    buildStats,
     buildId,
     nextExport: true,
     assetPrefix: nextConfig.assetPrefix.replace(/\/$/, ''),

server/index.js

@@ -49,8 +49,6 @@ export default class Server {
       console.error(`> Could not find a valid build in the '${this.dist}' directory! Try building your app with 'next build' before starting the server.`)
       process.exit(1)
     }
-
-    this.buildStats = !dev ? require(join(this.dir, this.dist, 'build-stats.json')) : null
     this.buildId = !dev ? this.readBuildId() : '-'
     this.renderOpts = {
       dev,
@@ -58,7 +56,6 @@ export default class Server {
       dir: this.dir,
       dist: this.dist,
       hotReloader: this.hotReloader,
-      buildStats: this.buildStats,
       buildId: this.buildId,
       availableChunks: dev ? {} : getAvailableChunks(this.dir, this.dist)
     }
@@ -170,27 +167,22 @@ export default class Server {
       },
 
       '/_next/:hash/main.js': async (req, res, params) => {
-        if (!this.dev) return this.send404(res)
+        if (this.dev) {
+          this.handleBuildHash('main.js', params.hash, res)
+          const p = join(this.dir, this.dist, 'main.js')
+          await this.serveStatic(req, res, p)
+        } else {
+          const buildId = params.hash
+          if (!this.handleBuildId(buildId, res)) {
+            const error = new Error('INVALID_BUILD_ID')
+            const customFields = { buildIdMismatched: true }
 
-        this.handleBuildHash('main.js', params.hash, res)
-        const p = join(this.dir, this.dist, 'main.js')
-        await this.serveStatic(req, res, p)
-      },
+            return await renderScriptError(req, res, '/_error', error, customFields, this.renderOpts)
+          }
 
-      '/_next/:hash/commons.js': async (req, res, params) => {
-        if (!this.dev) return this.send404(res)
-
-        this.handleBuildHash('commons.js', params.hash, res)
-        const p = join(this.dir, this.dist, 'commons.js')
-        await this.serveStatic(req, res, p)
-      },
-
-      '/_next/:hash/app.js': async (req, res, params) => {
-        if (this.dev) return this.send404(res)
-
-        this.handleBuildHash('app.js', params.hash, res)
-        const p = join(this.dir, this.dist, 'app.js')
-        await this.serveStatic(req, res, p)
+          const p = join(this.dir, this.dist, 'main.js')
+          await this.serveStatic(req, res, p)
+        }
       },
 
       '/_next/:buildId/page/:path*.js.map': async (req, res, params) => {
@@ -466,10 +458,6 @@ export default class Server {
       return true
     }
 
-    if (hash !== this.buildStats[filename].hash) {
-      throw new Error(`Invalid Build File Hash(${hash}) for chunk: ${filename}`)
-    }
-
     res.setHeader('Cache-Control', 'max-age=31536000, immutable')
     return true
   }

server/render.js

@@ -37,7 +37,6 @@ async function doRender (req, res, pathname, query, {
   err,
   page,
   buildId,
-  buildStats,
   hotReloader,
   assetPrefix,
   runtimeConfig,
@@ -108,7 +107,6 @@ async function doRender (req, res, pathname, query, {
       pathname, // the requested path
       query,
       buildId,
-      buildStats,
       assetPrefix,
       runtimeConfig,
       nextExport,

test/integration/dist-dir/test/index.test.js

@@ -39,11 +39,11 @@ describe('Production Usage', () => {
 
   describe('File locations', () => {
     it('should build the app within the given `dist` directory', () => {
-      expect(existsSync(join(__dirname, '/../dist/app.js'))).toBeTruthy()
+      expect(existsSync(join(__dirname, '/../dist/main.js'))).toBeTruthy()
     })
 
     it('should not build the app within the default `.next` directory', () => {
-      expect(existsSync(join(__dirname, '/../.next/app.js'))).toBeFalsy()
+      expect(existsSync(join(__dirname, '/../.next/main.js'))).toBeFalsy()
     })
   })
 })