[optimize] More aggressive chunking of common/vendor code

Previously, we were not aggressive in combining common code which resulted in duplicates included in the bundles.

As an example `node_modules/elasticsearch-browser/elasticsearch.angular.js` is present in the following chunks:

* kibana.bundle.js
* dashboardViewer.bundle.js
* apm.bundle.js
* monitoring.bundle.js
* ml.bundle.js
* timelion.bundle.js
* graph.bundle.js

Vendored code (anything inside node_modules) is placed in vendors.bundle.js while everything else with more than two references is placed in commons.bundle.js.

This has a couple positive side-effects (numbers are with x-pack & canvas):

* Decreased build time. Seeing builds go from 475.76 seconds to 274.72.
* Decreased memory overhead. Uses roughly 1/3 the memory overhead and overwriting `--max-old-space-size` is no longer necessary.
* Decreased bundle size. A 68% reduction in overall bundle size. Going from 66.16 MB to 21.13 MB.

Signed-off-by: Tyler Smalley <tyler.smalley@elastic.co>

src/optimize/base_optimizer.js

@@ -4,10 +4,6 @@ import { writeFile } from 'fs';
 import Boom from 'boom';
 import ExtractTextPlugin from 'extract-text-webpack-plugin';
 import webpack from 'webpack';
-import CommonsChunkPlugin from 'webpack/lib/optimize/CommonsChunkPlugin';
-import DefinePlugin from 'webpack/lib/DefinePlugin';
-import UglifyJsPlugin from 'webpack/lib/optimize/UglifyJsPlugin';
-import NoEmitOnErrorsPlugin from 'webpack/lib/NoEmitOnErrorsPlugin';
 import Stats from 'webpack/lib/Stats';
 import webpackMerge from 'webpack-merge';
 
@@ -122,12 +118,19 @@ export default class BaseOptimizer {
           allChunks: true
         }),
 
-        new CommonsChunkPlugin({
+        new webpack.optimize.CommonsChunkPlugin({
           name: 'commons',
-          filename: 'commons.bundle.js'
+          filename: 'commons.bundle.js',
+          minChunks: 2,
         }),
 
-        new NoEmitOnErrorsPlugin(),
+        new webpack.optimize.CommonsChunkPlugin({
+          name: 'vendors',
+          filename: 'vendors.bundle.js',
+          minChunks: module => module.context && module.context.indexOf('node_modules') !== -1
+        }),
+
+        new webpack.NoEmitOnErrorsPlugin(),
       ],
 
       module: {
@@ -225,12 +228,12 @@ export default class BaseOptimizer {
 
     return webpackMerge(commonConfig, {
       plugins: [
-        new DefinePlugin({
+        new webpack.DefinePlugin({
           'process.env': {
             'NODE_ENV': '"production"'
           }
         }),
-        new UglifyJsPlugin({
+        new webpack.optimize.UglifyJsPlugin({
           compress: {
             warnings: false
           },

src/ui/ui_render/views/ui_app.jade

@@ -120,8 +120,10 @@ block content
         return anchor.href;
       }
       var files = [
+        bundleFile('vendors.style.css'),
         bundleFile('commons.style.css'),
         bundleFile('#{app.getId()}.style.css'),
+        bundleFile('vendors.bundle.js'),
         bundleFile('commons.bundle.js'),
         bundleFile('#{app.getId()}.bundle.js')
       ];

tasks/config/karma.js

@@ -37,8 +37,10 @@ module.exports = function (grunt) {
 
       // list of files / patterns to load in the browser
       files: [
+        'http://localhost:5610/bundles/vendors.bundle.js',
         'http://localhost:5610/bundles/commons.bundle.js',
         'http://localhost:5610/bundles/tests.bundle.js',
+        'http://localhost:5610/bundles/vendors.style.css',
         'http://localhost:5610/bundles/commons.style.css',
         'http://localhost:5610/bundles/tests.style.css'
       ],