From ea5d598c9f90a26603c4e22eb7e2c5d3ff5ef5d6 Mon Sep 17 00:00:00 2001
From: Birk Johansson <birk@dhis2.org>
Date: Wed, 7 Sep 2022 02:17:52 +0200
Subject: [PATCH] fix: deduplicate identical mutations

---
 src/app/query-client/use-query-client.js | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/src/app/query-client/use-query-client.js b/src/app/query-client/use-query-client.js
index 99950b352..2b622b51d 100644
--- a/src/app/query-client/use-query-client.js
+++ b/src/app/query-client/use-query-client.js
@@ -25,6 +25,25 @@ const useQueryClient = () => {
         },
     })
 
+    const mutationCache = queryClient.getMutationCache()
+    // prevent duplicate mutations from being stored in cache
+    mutationCache.subscribe((event) => {
+        if (event.type !== 'updated') {
+            return
+        }
+        const { mutation } = event
+        const duplicateMutation = mutationCache.find({
+            mutationKey: mutation.options.mutationKey,
+            // ensure previous mutation was fired before this
+            // (mutationId is an incremental integer)
+            predicate: (currMutation) =>
+                currMutation.mutationId < mutation.mutationId,
+        })
+        if (duplicateMutation) {
+            mutationCache.remove(duplicateMutation)
+        }
+    })
+
     return queryClient
 }