From 891abb626b88c5b51ebc6249999b17ab651d8b3b Mon Sep 17 00:00:00 2001
From: Ben Briggs <ben.briggs@thedistance.co.uk>
Date: Wed, 26 Sep 2018 17:44:49 +0100
Subject: [PATCH] Ensure that setting a value to undefined is a no-op on
 writes. (#5065)

---
 src/Adapters/Storage/Postgres/PostgresStorageAdapter.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js b/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js
index f996367143..6c6a47020d 100644
--- a/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js
+++ b/src/Adapters/Storage/Postgres/PostgresStorageAdapter.js
@@ -1442,7 +1442,10 @@ export class PostgresStorageAdapter implements StorageAdapter {
 
     for (const fieldName in update) {
       const fieldValue = update[fieldName];
-      if (fieldValue === null) {
+      // Drop any undefined values.
+      if (typeof fieldValue === 'undefined') {
+        delete update[fieldName];
+      } else if (fieldValue === null) {
         updatePatterns.push(`$${index}:name = NULL`);
         values.push(fieldName);
         index += 1;