fix renderers in core plugin

lib/plugins/core.js

@@ -4,6 +4,28 @@ import keycode from 'keycode'
 import { isCommand, isCtrl, isWindowsCommand, isWord } from '../utils/event'
 import { IS_WINDOWS, IS_MAC } from '../utils/environment'
 
+/**
+ * Default block renderer.
+ */
+
+const DEFAULT_BLOCK = props => <div>{props.children}</div>
+
+/**
+ * Default inline renderer.
+ *
+ * @type {Component}
+ */
+
+const DEFAULT_INLINE = props => <span>{props.children}</span>
+
+/**
+ * Default mark renderer.
+ *
+ * @type {Object}
+ */
+
+const DEFAULT_MARK = {}
+
 /**
  * Export.
  */
@@ -121,7 +143,7 @@ export default {
   },
 
   /**
-   * The core `onPaste` handler.
+   * The core `onPaste` handler, which treats everything as plain text.
    *
    * @param {Event} e
    * @param {Object} paste
@@ -146,7 +168,8 @@ export default {
   },
 
   /**
-   * Default `node` renderer.
+   * The core `node` renderer, which uses plain `<div>` or `<span>` depending on
+   * what kind of node it is.
    *
    * @param {Node} node
    * @return {Component} component
@@ -154,19 +177,19 @@ export default {
 
   renderNode(node) {
     return node.kind == 'block'
-      ? (props) => <div>{props.children}</div>
+      ? DEFAULT_BLOCK
-      : (props) => <span>{props.children}</span>
+      : DEFAULT_INLINE
   },
 
   /**
-   * Default `mark` renderer.
+   * The core `mark` renderer, with no styles.
    *
    * @param {Mark} mark
    * @return {Object} style
    */
 
   renderMark(mark) {
-    return {}
+    return DEFAULT_MARK
   }
 
 }