add getHighestChild

lib/models/node.js

@@ -95,19 +95,12 @@ const Node = {
     // Then remove any nodes in between the top-most start and end nodes...
     let startParent = node.getParent(startKey)
     let endParent = node.getParent(endKey)
-
-    const startGrandestParent = node.nodes.find((child) => {
-      return child == startParent || child.hasDescendant(startParent)
-    })
-
-    const endGrandestParent = node.nodes.find((child) => {
-      return child == endParent || child.hasDescendant(endParent)
-    })
-
+    const startAncestor = node.getHighestChild(startParent)
+    const endAncestor = node.getHighestChild(endParent)
     const nodes = node.nodes
-      .takeUntil(child => child == startGrandestParent)
-      .push(startGrandestParent)
-      .concat(node.nodes.skipUntil(child => child == endGrandestParent))
+      .takeUntil(child => child == startAncestor)
+      .push(startAncestor)
+      .concat(node.nodes.skipUntil(child => child == endAncestor))
 
     node = node.merge({ nodes })
 
@@ -320,6 +313,22 @@ const Node = {
     return this.nodes.find(node => node.key == key)
   },
 
+  /**
+   * Get the highest child ancestor of a node by `key`.
+   *
+   * @param {String or Node} key
+   * @return {Node or Null} node
+   */
+
+  getHighestChild(key) {
+    key = normalizeKey(key)
+    return this.nodes.find(node => {
+      if (node.key == key) return true
+      if (node.kind == 'text') return false
+      return node.hasDescendant(key)
+    })
+  },
+
   /**
    * Get a descendant node by `key`.
    *