From 38cd1926716f9ef2db69ec5b136fc862c3c90b87 Mon Sep 17 00:00:00 2001
From: Robin Ricard <ricard.robin@gmail.com>
Date: Fri, 22 Jul 2016 18:44:51 +0200
Subject: [PATCH] Performs a list merging that looks for IDs

By looking of ID fields we can handle complex cases such as updating at the same time two nested arrays.
---
 src/data/writeToStore.ts | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/data/writeToStore.ts b/src/data/writeToStore.ts
index 06741a82f1d..219453b9a89 100644
--- a/src/data/writeToStore.ts
+++ b/src/data/writeToStore.ts
@@ -294,7 +294,7 @@ function writeFieldToStore({
         fragmentMap,
         included: true,
       });
-      value = [].concat(oldValue, value);
+      value = defaultListMerging(oldValue, value);
     }
 
     value.forEach((item, index) => {
@@ -409,3 +409,9 @@ function writeFieldToStore({
   }
 
 }
+
+function defaultListMerging(oldValues: any[], newValues: any[]): any[] {
+  const newIds = newValues.map(value => value.id ? value.id : null) .filter(id => id !== null);
+  const filteredOldValues = oldValues.filter(value => !value.id || newIds.indexOf(value.id) < 0);
+  return [].concat(filteredOldValues, newValues);
+}