diff --git a/shared-lib/lib-ot/src/core/document/document_operation.rs b/shared-lib/lib-ot/src/core/document/document_operation.rs
index 7b7b0c4a62..ff1a968af5 100644
--- a/shared-lib/lib-ot/src/core/document/document_operation.rs
+++ b/shared-lib/lib-ot/src/core/document/document_operation.rs
@@ -1,6 +1,7 @@
 use crate::core::document::position::Position;
 use crate::core::{NodeAttributes, NodeData, TextDelta};
 
+#[derive(Clone)]
 pub enum DocumentOperation {
     Insert(InsertOperation),
     Update(UpdateOperation),
@@ -31,24 +32,31 @@ impl DocumentOperation {
             }),
         }
     }
+    pub fn transform(_a: &DocumentOperation, b: &DocumentOperation) -> DocumentOperation {
+        b.clone()
+    }
 }
 
+#[derive(Clone)]
 pub struct InsertOperation {
     pub path: Position,
     pub nodes: Vec<NodeData>,
 }
 
+#[derive(Clone)]
 pub struct UpdateOperation {
     pub path: Position,
     pub attributes: NodeAttributes,
     pub old_attributes: NodeAttributes,
 }
 
+#[derive(Clone)]
 pub struct DeleteOperation {
     pub path: Position,
     pub nodes: Vec<NodeData>,
 }
 
+#[derive(Clone)]
 pub struct TextEditOperation {
     pub path: Position,
     pub delta: TextDelta,
diff --git a/shared-lib/lib-ot/src/core/document/position.rs b/shared-lib/lib-ot/src/core/document/position.rs
index 34e0c784d5..b463f207da 100644
--- a/shared-lib/lib-ot/src/core/document/position.rs
+++ b/shared-lib/lib-ot/src/core/document/position.rs
@@ -5,6 +5,38 @@ impl Position {
     pub fn is_empty(&self) -> bool {
         self.0.is_empty()
     }
+    pub fn len(&self) -> usize {
+        self.0.len()
+    }
+}
+
+impl Position {
+    // delta is default to be 1
+    pub fn transform(pre_insert_path: &Position, b: &Position, delta: usize) -> Position {
+        if pre_insert_path.len() > b.len() {
+            return b.clone();
+        }
+        if pre_insert_path.is_empty() || b.is_empty() {
+            return b.clone();
+        }
+        // check the prefix
+        for i in 0..(pre_insert_path.len()) {
+            if pre_insert_path.0[i] != b.0[i] {
+                return b.clone();
+            }
+        }
+        let mut prefix: Vec<usize> = pre_insert_path.0[0..(pre_insert_path.len() - 1)].into();
+        let mut suffix: Vec<usize> = b.0[pre_insert_path.0.len()..].into();
+        let prev_insert_last: usize = *pre_insert_path.0.last().unwrap();
+        let b_at_index = b.0[pre_insert_path.0.len() - 1];
+        if prev_insert_last <= b_at_index {
+            prefix.push(b_at_index + delta);
+        } else {
+            prefix.push(b_at_index);
+        }
+        prefix.append(&mut suffix);
+        return Position(prefix);
+    }
 }
 
 impl From<Vec<usize>> for Position {
diff --git a/shared-lib/lib-ot/src/core/document/transaction.rs b/shared-lib/lib-ot/src/core/document/transaction.rs
index f240b8ea89..c0e7cc3243 100644
--- a/shared-lib/lib-ot/src/core/document/transaction.rs
+++ b/shared-lib/lib-ot/src/core/document/transaction.rs
@@ -1,6 +1,8 @@
-use std::collections::HashMap;
 use crate::core::document::position::Position;
-use crate::core::{DeleteOperation, DocumentOperation, DocumentTree, InsertOperation, NodeAttributes, NodeData, UpdateOperation};
+use crate::core::{
+    DeleteOperation, DocumentOperation, DocumentTree, InsertOperation, NodeAttributes, NodeData, UpdateOperation,
+};
+use std::collections::HashMap;
 
 pub struct Transaction {
     pub operations: Vec<DocumentOperation>,
diff --git a/shared-lib/lib-ot/tests/main.rs b/shared-lib/lib-ot/tests/main.rs
index c2e0226eb6..f6d5aa6ace 100644
--- a/shared-lib/lib-ot/tests/main.rs
+++ b/shared-lib/lib-ot/tests/main.rs
@@ -1,5 +1,5 @@
-use std::collections::HashMap;
 use lib_ot::core::{DocumentTree, NodeData, TransactionBuilder};
+use std::collections::HashMap;
 
 #[test]
 fn main() {
@@ -21,9 +21,10 @@ fn test_documents() {
     assert_eq!(node_data.node_type, "text");
 
     let mut tb = TransactionBuilder::new(&document);
-    tb.update_attributes(&vec![0].into(), HashMap::from([
-        ("subtype".into(), Some("bullet-list".into())),
-    ]));
+    tb.update_attributes(
+        &vec![0].into(),
+        HashMap::from([("subtype".into(), Some("bullet-list".into()))]),
+    );
     let transaction = tb.finalize();
     document.apply(transaction);