Use ISO datetime parsing

src/services/history/organiseHistory.ts

@@ -1,3 +1,5 @@
+import { format, formatISO } from "date-fns";
+
 import { HistoryItem, OrganisedHistory } from "./types";
 
 /**
@@ -7,19 +9,19 @@ import { HistoryItem, OrganisedHistory } from "./types";
 export const organiseHistory = (history: HistoryItem[]): OrganisedHistory => {
   const grouped = history.reduce<OrganisedHistory>((acc, item) => {
     const date = new Date(item.lastVisitTime || 0);
-    const [dateString] = date.toISOString().split("T");
-    const hourString = date.getHours().toString().padStart(2, "0");
+    const dateKey = formatISO(date, { representation: "date" });
+    const hourKey = format(date, "HH");
 
-    if (!acc.has(dateString)) {
-      acc.set(dateString, new Map());
+    if (!acc.has(dateKey)) {
+      acc.set(dateKey, new Map());
     }
-    const dayMap = acc.get(dateString)!;
 
-    if (!dayMap.has(hourString)) {
-      dayMap.set(hourString, []);
+    const dayMap = acc.get(dateKey)!;
+    if (!dayMap.has(hourKey)) {
+      dayMap.set(hourKey, []);
     }
-    dayMap.get(hourString)!.push(item);
 
+    dayMap.get(hourKey)!.push(item);
     return acc;
   }, new Map());