From 477a9d5c02b2f1ede1ebfa8c0c4f396562303262 Mon Sep 17 00:00:00 2001
From: mahula <lenzmath@posteo.de>
Date: Thu, 20 Nov 2025 20:10:31 +0100
Subject: [PATCH] fix: prevent duplicate API instances in MapContainer - fixed
 state management bug where API instances were appended to existing array
 instead of replacing it - this caused duplicate API instances in React Strict
 Mode and potential memory leaks - replaced setApis((current) => [...current,
 newApi]) with proper array replacement

- compute full API array from layers, then replace state completely
- use .map() for transformation instead of side effects
- the apis array has 1:1 relationship with layers (matched by ID), so accumulation was never intended
---
 app/src/pages/MapContainer.tsx | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/app/src/pages/MapContainer.tsx b/app/src/pages/MapContainer.tsx
index 4bf983a4..44f73bea 100644
--- a/app/src/pages/MapContainer.tsx
+++ b/app/src/pages/MapContainer.tsx
@@ -36,12 +36,12 @@ function MapContainer({ layers, map }: { layers: LayerProps[]; map: any }) {
   const [apis, setApis] = useState<layerApi[]>([])
 
   useEffect(() => {
-    // get timestamp for the end of the current day
+    // get timestamp for the start of the current day
     const now = new Date()
     const startOfDay = new Date(now.getFullYear(), now.getMonth(), now.getDate())
     const startOfDayISO = startOfDay.toISOString()
 
-    layers.map((layer: LayerProps) => {
+    const newApis = layers.map((layer: LayerProps) => {
       // Only apply date filter if showPastItems is not explicitly set to true
       const dateFilter = layer.showPastItems
         ? undefined
@@ -60,15 +60,13 @@ function MapContainer({ layers, map }: { layers: LayerProps[]; map: any }) {
             ],
           }
 
-      apis &&
-        setApis((current) => [
-          ...current,
-          {
-            id: layer.id,
-            api: new itemsApi<Place>('items', layer.id, undefined, dateFilter),
-          },
-        ])
+      return {
+        id: layer.id,
+        api: new itemsApi<Place>('items', layer.id, undefined, dateFilter),
+      }
     })
+
+    setApis(newApis)
   }, [layers])
 
   useEffect(() => {}, [apis])