Koenig - Added SHIFT+ENTER line break key command

refs https://github.com/TryGhost/Ghost/issues/9311
- pressing <kbd>Shift+Enter</kbd> will create a `soft-return` atom that adds a `<br>` element to the doc
- emulates many rich-text editors that have a similar functionality where it's desirable to add line breaks rather than starting new paragraphs

lib/koenig-editor/addon/components/koenig-editor.js

@@ -6,7 +6,9 @@
 import Component from '@ember/component';
 import Editor from 'mobiledoc-kit/editor/editor';
 import Ember from 'ember';
+import defaultAtoms from '../options/atoms';
 import layout from '../templates/components/koenig-editor';
+import registerKeyCommands from '../options/key-commands';
 import registerTextExpansions from '../options/text-expansions';
 import {MOBILEDOC_VERSION} from 'mobiledoc-kit/renderers/mobiledoc';
 import {assign} from '@ember/polyfills';
@@ -79,11 +81,17 @@ export default Component.extend({
     // merge in named options with the `options` property data-bag
     editorOptions: computed(function () {
         let options = this.get('options') || {};
+        let atoms = this.get('atoms') || [];
+
+        // add our default atoms, we want the defaults to be first so that they
+        // can be overridden by any passed-in atoms
+        atoms = Array.concat(defaultAtoms, atoms);
 
         return assign({
             placeholder: this.get('placeholder'),
             spellcheck: this.get('spellcheck'),
-            autofocus: this.get('autofocus')
+            autofocus: this.get('autofocus'),
+            atoms
         }, options);
     }),
 
@@ -136,6 +144,9 @@ export default Component.extend({
         editor = new Editor(editorOptions);
 
         // set up key commands and text expansions (MD conversion)
+        // TODO: this will override any passed in options, we should allow the
+        // default behaviour to be overridden by addon consumers
+        registerKeyCommands(editor);
         registerTextExpansions(editor);
 
         // set up editor hooks

lib/koenig-editor/addon/options/atoms.js

@@ -0,0 +1,14 @@
+// Atoms are effectively read-only inline cards
+// Full docs: https://github.com/bustle/mobiledoc-kit/blob/master/ATOMS.md
+
+export default [
+    // soft-return is triggered by SHIFT+ENTER and allows for line breaks
+    // without creating paragraphs
+    {
+        name: 'soft-return',
+        type: 'dom',
+        render() {
+            return document.createElement('br');
+        }
+    }
+];

lib/koenig-editor/addon/options/key-commands.js

@@ -0,0 +1,16 @@
+// Key commands will run any time a particular key or key combination is pressed
+// https://github.com/bustlelabs/mobiledoc-kit#configuring-hot-keys
+
+export default function (editor) {
+    let softReturnKeyCommand = {
+        str: 'SHIFT+ENTER',
+
+        run(editor) {
+            editor.run((postEditor) => {
+                let softReturn = postEditor.builder.createAtom('soft-return');
+                postEditor.insertMarkers(editor.range.head, [softReturn]);
+            });
+        }
+    };
+    editor.registerKeyCommand(softReturnKeyCommand);
+}

yarn.lock

@@ -3233,13 +3233,6 @@ ember-cli-string-helpers@1.0.0:
     broccoli-funnel "^1.0.1"
     ember-cli-babel "^5.1.7"
 
-ember-cli-string-helpers@1.6.0:
-  version "1.6.0"
-  resolved "https://registry.yarnpkg.com/ember-cli-string-helpers/-/ember-cli-string-helpers-1.6.0.tgz#dd38cdf3cddaaf8bb62f58d83fcc4e8d47a2e89d"
-  dependencies:
-    broccoli-funnel "^1.0.1"
-    ember-cli-babel "^6.6.0"
-
 "ember-cli-string-helpers@https://github.com/kevinansfield/ember-cli-string-helpers.git#9fda91b34a00e3365833527605b44399f36432d5":
   version "1.6.0"
   resolved "https://github.com/kevinansfield/ember-cli-string-helpers.git#9fda91b34a00e3365833527605b44399f36432d5"