moveNode operation fix (#782)

* Fix `moveNode` operation.
When `parent` is an ancestor of `target` and the index of `node` is
less than the index of the ancestor of `target` with the same depth
of `node`, removing `node` changes the path to `target`.
As consequence of that, `newPath` needs to be adjusted.

* Add test.

* Improve code.

src/transforms/apply-operation.js

@@ -187,19 +187,42 @@ function moveNode(state, operation) {
   const { path, newPath, newIndex } = operation
   let { document } = state
   const node = document.assertPath(path)
+  const index = path.pop()
+  const parentDepth = path.length
 
   // Remove the node from its current parent
   let parent = document.getParent(node.key)
-  const isParent = document == parent
-  const index = parent.nodes.indexOf(node)
   parent = parent.removeNode(index)
-  document = isParent ? parent : document.updateDescendant(parent)
+  document = parent.kind === 'document' ? parent : document.updateDescendant(parent)
+
+  // Check if `parent` is an anchestor of `target`
+  const isAncestor = path.every((x, i) => x === newPath[i])
+
+  let target
+
+  // If `parent` ia an ancestor of `target` and they have the same depth,
+  // then `parent` and `target` are the same node.
+  if (isAncestor && parentDepth === newPath.length) {
+    target = parent
+  }
+
+  // Else if `parent` is an ancestor of `target` and `node` index is less than
+  // the index of the `target` ancestor with the same depth of `node`,
+  // then removing `node` changes the path to `target`.
+  // So we have to adjust `newPath` before picking `target`.
+  else if (isAncestor && index < newPath[parentDepth]) {
+    newPath[parentDepth]--
+    target = document.assertPath(newPath)
+  }
+
+  // Else pick `target`
+  else {
+    target = document.assertPath(newPath)
+  }
 
   // Insert the new node to its new parent
-  let target = document.assertPath(newPath)
-  const isTarget = document == target
   target = target.insertNode(newIndex, node)
-  document = isTarget ? target : document.updateDescendant(target)
+  document = target.kind === 'document' ? target : document.updateDescendant(target)
 
   state = state.set('document', document)
   return state

test/transforms/fixtures/by-key/move-node-by-key/to-sibling/index.js

@@ -0,0 +1,11 @@
+
+export default function (state) {
+  const { document, selection } = state
+  const first = document.getBlocks().first()
+  const container = document.nodes.last()
+
+  return state
+    .transform()
+    .moveNodeByKey(first.key, container.key, 1)
+    .apply()
+}

test/transforms/fixtures/by-key/move-node-by-key/to-sibling/input.yaml

@@ -0,0 +1,15 @@
+
+nodes:
+  - kind: block
+    type: paragraph
+    nodes:
+      - kind: text
+        text: one
+  - kind: block
+    type: container
+    nodes:
+      - kind: block
+        type: paragraph
+        nodes:
+          - kind: text
+            text: two

test/transforms/fixtures/by-key/move-node-by-key/to-sibling/output.yaml

@@ -0,0 +1,15 @@
+
+nodes:
+  - kind: block
+    type: container
+    nodes:
+      - kind: block
+        type: paragraph
+        nodes:
+          - kind: text
+            text: two
+      - kind: block
+        type: paragraph
+        nodes:
+          - kind: text
+            text: one