Add deep option to joinNode to allow correctly undoing splitNode

src/models/node.js

@@ -1137,10 +1137,13 @@ const Node = {
    *
    * @param {Node} first
    * @param {Node} second
+   * @param {Boolean} options.deep (optional) Join recursively the
+   * respective last node and first node of the nodes' children. Like a zipper :)
    * @return {Node}
    */
 
-  joinNode(first, second) {
+  joinNode(first, second, options) {
+    const { deep = false } = options
     let node = this
     let parent = node.getParent(second.key)
     const isParent = node == parent
@@ -1157,6 +1160,11 @@ const Node = {
       second.nodes.forEach((child, i) => {
         first = first.insertNode(size + i, child)
       })
+
+      if (deep) {
+        // Join recursively
+        first = first.joinNode(first.nodes.get(size - 1), first.nodes.get(size), { deep })
+      }
     }
 
     parent = parent.removeNode(index)

src/transforms/apply-operation.js

@@ -132,33 +132,41 @@ function insertText(state, operation) {
  *
  * @param {State} state
  * @param {Object} operation
+ *   @param {Boolean} operation.deep (optional) Join recursively the
+ *   respective last node and first node of the nodes' children. Like a zipper :)
  * @return {State}
  */
 
 function joinNode(state, operation) {
-  const { path, withPath } = operation
+  const { path, withPath, deep = false } = operation
   let { document, selection } = state
   const first = document.assertPath(withPath)
   const second = document.assertPath(path)
 
   // Update doc
-  document = document.joinNode(first, second)
+  document = document.joinNode(first, second, { deep })
+
+  // Update selection if we merged two texts together
+  if (deep || second.kind == 'text') {
+    const firstText = deep
+            ? first.getLastText()
+            : first
+    const secondText = deep
+            ? second.getFirstText()
+            : second
 
-  // Update selection
-  // When merging two texts together
-  if (second.kind == 'text') {
     const { anchorKey, anchorOffset, focusKey, focusOffset } = selection
     // The final key is the `first` key
-    if (anchorKey == second.key) {
+    if (anchorKey == secondText.key) {
       selection = selection.merge({
-        anchorKey: first.key,
+        anchorKey: firstText.key,
-        anchorOffset: anchorOffset + first.characters.size
+        anchorOffset: anchorOffset + firstText.characters.size
       })
     }
-    if (focusKey == second.key) {
+    if (focusKey == secondText.key) {
       selection = selection.merge({
-        focusKey: first.key,
+        focusKey: firstText.key,
-        focusOffset: focusOffset + first.characters.size
+        focusOffset: focusOffset + firstText.characters.size
       })
     }
   }

src/transforms/operations.js

@@ -445,12 +445,14 @@ export function setSelectionOperation(transform, properties) {
  */
 
 export function splitNodeOperation(transform, path, offset) {
-  const inverseIndex = path[path.length - 1] + 1
+  const inversePath = path.slice()
-  const inversePath = path.slice(0, -1).concat([inverseIndex])
+  inversePath[path.length - 1] += 1
+
   const inverse = [{
     type: 'join_node',
     path: inversePath,
     withPath: path,
+    deep: true // we need to join nodes recursively
   }]
 
   const operation = {