Fix for issue frontend-collective#369 (frontend-collective#461)

* Fix issue frontend-collective#369

* Better naming, use of const

Co-Authored-By: HgAlexx <alex@mzhg.space>

* Better naming

Co-Authored-By: HgAlexx <alex@mzhg.space>

Author: HgAlexx

src/react-sortable-tree.js

@@ -155,10 +155,12 @@ class ReactSortableTree extends Component {
     const { instanceProps } = prevState;
     const newState = {};
 
+    const isTreeDataEqual = isEqual(instanceProps.treeData, nextProps.treeData);
+
     // make sure we have the most recent version of treeData
     instanceProps.treeData = nextProps.treeData;
 
-    if (!isEqual(instanceProps.treeData, nextProps.treeData)) {
+    if (!isTreeDataEqual) {
       if (instanceProps.ignoreOneTreeUpdate) {
         instanceProps.ignoreOneTreeUpdate = false;
       } else {