Lazy-load SimpleMDE dependency in MD card (reduces main bundle by 260KB)

no issue
- use broccoli-funnel to avoid polluting the `dist/` dir with unused build artefacts
- load codemirror and simplemde CSS up-front to avoid duplicate styles and specificity problems
- pull simplemde dependency out into a separate JS file and lazy-load in `{{gh-simplemde}}` component to reduce main bundle size. Before/after:
  - `vendor.min.js 3.58 MB (795.88 KB gzipped)`
  - `vendor.min.js 3.32 MB (710.66 KB gzipped)`

ghost/admin/app/components/gh-cm-editor.js

@@ -65,7 +65,6 @@ const CmEditorComponent = Component.extend({
         let loader = this.get('lazyLoader');
 
         yield RSVP.all([
-            loader.loadStyle('codemirror', 'assets/codemirror/codemirror.css'),
             loader.loadScript('codemirror', 'assets/codemirror/codemirror.js')
         ]);
 

ghost/admin/app/components/gh-simplemde.js

@@ -4,8 +4,11 @@ import config from 'ghost-admin/config/environment';
 import {assign} from '@ember/polyfills';
 import {computed} from '@ember/object';
 import {isEmpty} from '@ember/utils';
+import {inject as service} from '@ember/service';
+import {task} from 'ember-concurrency';
 
 export default TextArea.extend({
+    lazyLoader: service(),
 
     // Public attributes
     autofocus: false,
@@ -60,6 +63,18 @@ export default TextArea.extend({
     // instantiate the editor with the contents of value
     didInsertElement() {
         this._super(...arguments);
+        this.initSimpleMDE.perform();
+    },
+
+    willDestroyElement() {
+        this.onEditorDestroy();
+        this._editor.toTextArea();
+        delete this._editor;
+        this._super(...arguments);
+    },
+
+    initSimpleMDE: task(function* () {
+        yield this.lazyLoader.loadScript('simplemde', 'assets/simplemde/simplemde.js');
 
         let editorOptions = assign(
             {element: document.getElementById(this.elementId)},
@@ -97,12 +112,5 @@ export default TextArea.extend({
         }
 
         this.onEditorInit(this._editor);
-    },
+    })
-
-    willDestroyElement() {
-        this.onEditorDestroy();
-        this._editor.toTextArea();
-        delete this._editor;
-        this._super(...arguments);
-    }
 });

ghost/admin/app/styles/layouts/editor.css

@@ -378,6 +378,11 @@
 /* SimpleMDE editor
 /* ---------------------------------------------------------- */
 
+/* ensure there's no flash of unstyled textarea while initializing */
+.gh-markdown-editor textarea {
+    visibility: hidden;
+}
+
 .gh-editor-title {
     padding: 0;
 }

ghost/admin/ember-cli-build.js

@@ -6,20 +6,19 @@ const concat = require('broccoli-concat');
 const mergeTrees = require('broccoli-merge-trees');
 const uglify = require('broccoli-uglify-sourcemap');
 const CleanCSS = require('broccoli-clean-css');
+const Funnel = require('broccoli-funnel');
 const environment = EmberApp.env();
 const isProduction = environment === 'production';
-let assetLocation, codemirrorAssets;
 
-assetLocation = function (fileName) {
+const assetLocation = function (fileName) {
     if (isProduction) {
         fileName = fileName.replace('.', '.min.');
     }
     return `/assets/${fileName}`;
 };
 
-codemirrorAssets = function () {
+const codemirrorAssets = function () {
     let codemirrorFiles = [
-        // 'lib/codemirror.css',
         'theme/xq-light.css',
         'lib/codemirror.js',
         'mode/htmlmixed/htmlmixed.js',
@@ -45,17 +44,12 @@ codemirrorAssets = function () {
                 sourceMapConfig: {enabled: false}
             });
 
-            let cssTree = concat(tree, {
-                outputFile: 'assets/codemirror/codemirror.css',
-                inputFiles: ['**/*.css']
-            });
-
             if (isProduction) {
                 jsTree = uglify(jsTree);
-                cssTree = new CleanCSS(cssTree);
             }
 
-            return mergeTrees([tree, jsTree, cssTree]);
+            let mergedTree = mergeTrees([tree, jsTree]);
+            return new Funnel(mergedTree, {include: ['assets/**/*', 'theme/**/*']});
         }
     };
 
@@ -67,6 +61,44 @@ codemirrorAssets = function () {
     return config;
 };
 
+const simplemdeAssets = function () {
+    let simplemdeFiles = [
+        'debug/simplemde.js'
+    ];
+
+    if (environment === 'test') {
+        return {import: simplemdeFiles};
+    }
+
+    let config = {};
+
+    config.public = {
+        include: simplemdeFiles,
+        destDir: '/',
+        processTree(tree) {
+            let jsTree = concat(tree, {
+                outputFile: 'assets/simplemde/simplemde.js',
+                inputFiles: ['debug/simplemde.js'],
+                sourceMapConfig: {enabled: false}
+            });
+
+            if (isProduction) {
+                jsTree = uglify(jsTree);
+            }
+
+            let mergedTree = mergeTrees([tree, jsTree]);
+            return new Funnel(mergedTree, {include: ['assets/**/*']});
+        }
+    };
+
+    // put the files in vendor ready for importing into the test-support file
+    if (environment === 'development') {
+        config.vendor = simplemdeFiles;
+    }
+
+    return config;
+};
+
 module.exports = function (defaults) {
     let app = new EmberApp(defaults, {
         'ember-cli-babel': {
@@ -103,7 +135,8 @@ module.exports = function (defaults) {
             }
         },
         nodeAssets: {
-            codemirror: codemirrorAssets()
+            codemirror: codemirrorAssets(),
+            simplemde: simplemdeAssets()
         },
         svgJar: {
             strategy: 'inline',
@@ -130,14 +163,17 @@ module.exports = function (defaults) {
 
     // Stop: Normalize
     app.import('node_modules/normalize.css/normalize.css');
-    app.import('node_modules/simplemde/debug/simplemde.css');
+
+    // 'dem Styles
+    // import codemirror + simplemde styles rather than lazy-loading so that
+    // our overrides work correctly
+    app.import('node_modules/simplemde/dist/simplemde.min.css');
 
     // 'dem Scripts
     app.import('node_modules/google-caja-bower/html-css-sanitizer-bundle.js');
     app.import('node_modules/keymaster/keymaster.js');
     app.import('node_modules/@tryghost/mobiledoc-kit/dist/amd/mobiledoc-kit.js');
     app.import('node_modules/@tryghost/mobiledoc-kit/dist/amd/mobiledoc-kit.map');
-    app.import('node_modules/simplemde/debug/simplemde.js');
     app.import('node_modules/reframe.js/dist/noframe.es.js', {
         using: [
             {transformation: 'es6', as: 'noframe.js'}
@@ -148,6 +184,7 @@ module.exports = function (defaults) {
     // that tests don't break when running via http://localhost:4200/tests
     if (app.env === 'development') {
         app.import('vendor/codemirror/lib/codemirror.js', {type: 'test'});
+        app.import('vendor/simplemde/debug/simplemde.js', {type: 'test'});
     }
 
     return app.toTree();