diff --git a/README.md b/README.md
index e34a6829..17c55513 100644
--- a/README.md
+++ b/README.md
@@ -99,7 +99,7 @@ export default class Tree extends Component {
 | Prop                           |      Type      | <div style="width: 400px;">Description</div>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
 | :----------------------------- | :------------: | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
 | treeData<br/>_(required)_      |    object[]    | Tree data with the following keys: <div>`title` is the primary label for the node.</div><div>`subtitle` is a secondary label for the node.</div><div>`expanded` shows children of the node if true, or hides them if false. Defaults to false.</div><div>`children` is an array of child nodes belonging to the node.</div><div>**Example**: `[{title: 'main', subtitle: 'sub'}, { title: 'value2', expanded: true, children: [{ title: 'value3') }] }]`                                                                                                                                                                                           |
-| onChange<br/>_(required)_      |      func      | Called whenever tree data changed. Just like with React input elements, you have to update your own component's data to see the changes reflected.<div>`( treeData: object[] ): void`</div>                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
+| onChange<br/>_(required)_      |     func      | Called whenever tree data changed. Just like with React input elements, you have to update your own component's data to see the changes reflected.<div>`( treeData: object[], event: { changeActionType: 'move-iternal' \| 'move-external' \| 'expand' \| 'collapse' \| 'search' \| 'lazy-loaded' } ): void`</div>                                                                                                                                                                                                                                                            |
 | getNodeKey<br/>_(recommended)_ |      func      | Specify the unique key used to identify each node and generate the `path` array passed in callbacks. With a setting of `getNodeKey={({ node }) => node.id}`, for example, in callbacks this will let you easily determine that the node with an `id` of `35` is (or has just become) a child of the node with an `id` of `12`, which is a child of ... and so on. It uses [`defaultGetNodeKey`](./src/utils/default-handlers.ts) by default, which returns the index in the tree (omitting hidden nodes).<div>`({ node: object, treeIndex: number }): string or number`</div> |
 | generateNodeProps              |      func      | Generate an object with additional props to be passed to the node renderer. Use this for adding buttons via the `buttons` key, or additional `style` / `className` settings.<div>`({ node: object, path: number[] or string[], treeIndex: number, lowerSiblingCounts: number[], isSearchMatch: bool, isSearchFocus: bool }): object`</div>                                                                                                                                                                                                                                                                                                         |
 | onMoveNode                     |      func      | Called after node move operation. <div>`({ treeData: object[], node: object, nextParentNode: object, prevPath: number[] or string[], prevTreeIndex: number, nextPath: number[] or string[], nextTreeIndex: number }): void`</div>                                                                                                                                                                                                                                                                                                                                                                                                                  |
diff --git a/src/react-sortable-tree.tsx b/src/react-sortable-tree.tsx
index feaa90a8..20a51aa0 100644
--- a/src/react-sortable-tree.tsx
+++ b/src/react-sortable-tree.tsx
@@ -107,7 +107,7 @@ class ReactSortableTree extends Component {
     // Update the tree with data leaving all paths leading to matching nodes open
     if (expand) {
       newState.instanceProps.ignoreOneTreeUpdate = true // Prevents infinite loop
-      onChange(expandedTreeData)
+      onChange(expandedTreeData, { changeActionType: 'search' })
     }
 
     if (searchFinishCallback) {
@@ -168,7 +168,8 @@ class ReactSortableTree extends Component {
                         }
                       : oldNode,
                   getNodeKey: props.getNodeKey,
-                })
+                }),
+                { changeActionType: 'lazy-loaded' }
               ),
           })
         }
@@ -451,7 +452,7 @@ class ReactSortableTree extends Component {
         })
       }
 
-      this.props.onChange(treeData)
+      this.props.onChange(treeData, { changeActionType: 'move-external' })
 
       this.props.onMoveNode({
         treeData,
@@ -488,7 +489,7 @@ class ReactSortableTree extends Component {
       getNodeKey: this.props.getNodeKey,
     })
 
-    this.props.onChange(treeData)
+    this.props.onChange(treeData, { changeActionType: 'expand' })
 
     this.props.onVisibilityToggle({
       treeData,
@@ -519,7 +520,7 @@ class ReactSortableTree extends Component {
       getNodeKey: this.props.getNodeKey,
     })
 
-    this.props.onChange(treeData)
+    this.props.onChange(treeData, { changeActionType: 'move-internal' })
 
     this.props.onMoveNode({
       treeData,
@@ -768,6 +769,21 @@ type OnDragStateChangedParams = {
   draggedNode: any
 }
 
+// Available actions for the tree
+// move-internal: Move a node within the tree
+// move-external: Move a node from outside the tree
+// expand: Expand a node
+// collapse: Collapse a node
+// search: Search for nodes
+// lazy-loaded: Load lazy-loaded nodes
+type ChangeAction =
+  | 'move-iternal'
+  | 'move-external'
+  | 'expand'
+  | 'collapse'
+  | 'search'
+  | 'lazy-loaded'
+
 export type ReactSortableTreeProps = {
   dragDropManager?: {
     getMonitor: () => unknown
@@ -860,7 +876,7 @@ export type ReactSortableTreeProps = {
   // Called whenever tree data changed.
   // Just like with React input elements, you have to update your
   // own component's data to see the changes reflected.
-  onChange: (treeData) => void
+  onChange: (treeData, event: { changeActionType: ChangeAction }) => void
 
   // Called after node move operation.
   onMoveNode?: (params: OnMoveNodeParams) => void