From 242e3148c7211b11f72538ebe7eb9990e9bccfcf Mon Sep 17 00:00:00 2001
From: Tanner <git@tanner.vc>
Date: Tue, 25 Aug 2026 23:21:45 +0000
Subject: [PATCH] fix: use full timestamp as cache key in timezone conversion
 function

Co-authored-by: aider (gemini/gemini-3.1-pro-preview) <aider@aider.chat>
---
 client/src/App.js | 44 ++++++++++++++++----------------------------
 1 file changed, 16 insertions(+), 28 deletions(-)

diff --git a/client/src/App.js b/client/src/App.js
index 205ccc4..6cecca0 100644
--- a/client/src/App.js
+++ b/client/src/App.js
@@ -58,29 +58,18 @@ function useSensor(measurement, name, end, duration) {
 	const memoConvertTZ = (isDST, timeStr, format) => {
 		if (!timeStr) return '?';
 
-		let lookUp, result = null;
-		const date = timeStr.slice(5, 10);
-		const hours = timeStr.slice(11, 13);
-		const minutes = timeStr.slice(14, 16);
-
-		if (format === 'HH') {
-			lookUp = [isDST, hours, format];
-		} else {
-			lookUp = [isDST, date, format];
-		}
-
+		const lookUp = timeStr + format;
 		if (tzcache[lookUp] != undefined ) {
-			result = tzcache[lookUp];
-		} else {
-			result = moment(timeStr).tz('America/Edmonton').format(format);
-			tzcache[lookUp] = result;
+			return tzcache[lookUp];
 		}
 
+		let result = moment(timeStr).tz('America/Edmonton').format(format);
 		if (format === 'HH') {
-			return result + ':' + minutes;
-		} else {
-			return result;
+			const minutes = timeStr.slice(14, 16);
+			result = result + ':' + minutes;
 		}
+		tzcache[lookUp] = result;
+		return result;
 	};
 
 	const isDST = end.tz('America/Edmonton').isDST();
@@ -721,16 +710,15 @@ function MultiLineChart({title, measurement, dataKey, sensors, colors, end, dura
 
 	const memoConvertTZ = (isDST, timeStr, format) => {
 		if (!timeStr) return '?';
-		let lookUp, result = null;
-		const date = timeStr.slice(5, 10);
-		const hours = timeStr.slice(11, 13);
-		const minutes = timeStr.slice(14, 16);
-		if (format === 'HH') { lookUp = [isDST, hours, format]; }
-		else { lookUp = [isDST, date, format]; }
-		if (tzcache[lookUp] != undefined ) { result = tzcache[lookUp]; }
-		else { result = moment(timeStr).tz('America/Edmonton').format(format); tzcache[lookUp] = result; }
-		if (format === 'HH') { return result + ':' + minutes; }
-		else { return result; }
+		const lookUp = timeStr + format;
+		if (tzcache[lookUp] != undefined ) { return tzcache[lookUp]; }
+		let result = moment(timeStr).tz('America/Edmonton').format(format);
+		if (format === 'HH') {
+			const minutes = timeStr.slice(14, 16);
+			result = result + ':' + minutes;
+		}
+		tzcache[lookUp] = result;
+		return result;
 	};
 
 	const isDST = end.tz('America/Edmonton').isDST();