diff --git a/HISTORY.md b/HISTORY.md
index 63ed964..95b1945 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -3,6 +3,11 @@
 https://github.com/josdejong/jsoneditor
 
 
+## 2018-08-17, version 5.23.1
+
+- Fixed #566: transform function broken, regression since `v5.20.0`.
+
+
 ## 2018-08-15, version 5.23.0
 
 - Implemented support for custom validation using a new `onValidate` callback.
diff --git a/src/js/Node.js b/src/js/Node.js
index d2e5206..95cb815 100644
--- a/src/js/Node.js
+++ b/src/js/Node.js
@@ -3621,15 +3621,18 @@ Node.prototype.transform = function (query) {
 
   try {
     // apply the JMESPath query
-    var oldValue = this.getInternalValue();
-    var newValue = jmespath.search(oldValue, query);
+    var oldInternalValue = this.getInternalValue();
 
+    var oldValue = this.getValue();
+    var newValue = jmespath.search(oldValue, query);
     this.setValue(newValue);
 
+    var newInternalValue = this.getInternalValue();
+
     this.editor._onAction('transform', {
       path: this.getInternalPath(),
-      oldValue: oldValue,
-      newValue: this.getInternalValue()
+      oldValue: oldInternalValue,
+      newValue: newInternalValue
     });
 
     this.showChilds();