From 7e2941a8a6d34c66878a9981f98e181cd88a21c8 Mon Sep 17 00:00:00 2001
From: Tony Valle <tony@devotta.no>
Date: Fri, 10 Nov 2023 13:56:45 +0100
Subject: [PATCH] perf: remove unnecessary filter iterations

---
 .../Stages/Stages.component.js                | 25 +++++++++++++++----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/src/core_modules/capture-core/components/WidgetStagesAndEvents/Stages/Stages.component.js b/src/core_modules/capture-core/components/WidgetStagesAndEvents/Stages/Stages.component.js
index a56b467acf..7290bb6ac9 100644
--- a/src/core_modules/capture-core/components/WidgetStagesAndEvents/Stages/Stages.component.js
+++ b/src/core_modules/capture-core/components/WidgetStagesAndEvents/Stages/Stages.component.js
@@ -8,11 +8,26 @@ import { withLoadingIndicator } from '../../../HOC';
 
 const styles = {};
 export const StagesPlain = ({ stages, events, classes, ...passOnProps }: PlainProps) => {
-    const eventsByStage = useMemo(() => stages.reduce(
-        (acc, stage) => {
-            acc[stage.id] = events.filter(event => event.programStage === stage.id);
-            return acc;
-        }, {}), [stages, events],
+    const eventsByStage = useMemo(
+        () => stages.reduce(
+            (acc, stage) => {
+                acc[stage.id] = acc[stage.id] || [];
+                return acc;
+            },
+            events.reduce(
+                (acc, event) => {
+                    const stageId = event.programStage;
+                    if (acc[stageId]) {
+                        acc[stageId].push(event);
+                    } else {
+                        acc[stageId] = [event];
+                    }
+                    return acc;
+                },
+                {},
+            ),
+        ),
+        [stages, events],
     );
 
     return (<>