From 3ad163dc1dd8398d59b7d421f6c19c42b487e566 Mon Sep 17 00:00:00 2001
From: Luc Vidal <luc.vidal@360learning.com>
Date: Tue, 28 Jul 2026 18:54:30 +0200
Subject: [PATCH] feat: update doc to mention NO_UPDATE

---
 README.md | 28 +++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index b0ff53e..cef94b9 100644
--- a/README.md
+++ b/README.md
@@ -143,12 +143,34 @@ new MongoBulkDataMigration<Score>({
   collectionName: 'scores',
   projection: { scoreA: 1, scoreB: 1 },
   query: FETCH_ALL,
-  update: (doc) => {
+  update: (doc) => ({
     $set: {
-      total: doc.scoreA + doc.scoreB;
-    }
+      total: doc.scoreA + doc.scoreB,
+    },
+  }),
+});
+```
+
+### Conditional update on documents
+
+This migration will update documents depending on an external condition.
+Return the `NO_UPDATE` symbol to declare no update is needed.
+
+```ts
+import { MongoBulkDataMigration, NO_UPDATE } from "@360-l/mongo-bulk-data-migration";
+
+new MongoBulkDataMigration<Score>({
+  db,
+  id: 'conditional_update',
+  collectionName: 'scores',
+  query: FETCH_ALL,
+  update: async (doc) => {
+    if (! await shouldUpdate(doc)) { return NO_UPDATE; }
+    return { $set: { satus: "updated" } };
   },
 });
+
+async function shouldUpdate(...) // external check
 ```
 
 ### Automatic resume (`query: FETCH_ALL`)