add editor rule to ensure plain text in code blocks

src/components/Widgets/Markdown/MarkdownControl/VisualEditor/rules.js

@@ -40,6 +40,39 @@ const shortcodesAtRoot = {
   },
 };
 
-const rules = [ enforceNeverEmpty, shortcodesAtRoot ];
+/**
+ * Ensure that trailing shortcodes are followed by an empty paragraph.
+ */
+const noTrailingShortcodes = {
+  match: object => object.kind === 'document',
+  validate: doc => {
+    return doc.findDescendant(node => {
+      return node.type === 'shortcode' && doc.getBlocks().last().key === node.key;
+    });
+  },
+  normalize: (change, doc, node) => {
+    const text = Text.create('');
+    const block = Block.create({ type: 'paragraph', nodes: [ text ] });
+    return change.insertNodeByKey(doc.key, doc.get('nodes').size, block);
+  },
+};
+
+/**
+ * Ensure that code blocks contain no marks.
+ */
+const codeBlocksContainPlainText = {
+  match: node => node.type === 'code',
+  validate: node => {
+    const invalidChild = node.getTexts().find(text => !text.getMarks().isEmpty());
+    return invalidChild || null;
+  },
+  normalize: (change, node, invalidChild) => {
+    invalidChild.getMarks().forEach(mark => {
+      change.removeMarkByKey(invalidChild.key, 0, invalidChild.get('characters').size, mark);
+    });
+  },
+};
+
+const rules = [ enforceNeverEmpty, shortcodesAtRoot, codeBlocksContainPlainText ];
 
 export default rules;