group date pills when days are consecutive

web/src/lib/date.ts

@@ -1,4 +1,11 @@
-import { isToday, isAfter, parse, compareAsc } from "date-fns";
+import {
+  isToday,
+  isAfter,
+  parse,
+  compareAsc,
+  addDays,
+  isSameDay,
+} from "date-fns";
 import { nb } from "date-fns/locale";
 import { toZonedTime, format } from "date-fns-tz";
 
@@ -51,3 +58,53 @@ export function isTodayOrFuture(
 export function compareDates(a: Date | string, b: Date | string) {
   return compareAsc(new Date(a), new Date(b));
 }
+
+export function isConsectutiveDays(a: Date, b: Date): boolean {
+  const nextDay = addDays(a, 1);
+  return isSameDay(nextDay, b);
+}
+
+export function groupConsecutiveDates(dates: string[]): string[][] {
+  const groupedDates: string[][] = [];
+  let group: string[] = [];
+
+  for (let i = 0; i < dates.length; i++) {
+    if (
+      i === 0 ||
+      isConsectutiveDays(toLocalTime(dates[i - 1]), toLocalTime(dates[i]))
+    ) {
+      group.push(dates[i]);
+    } else {
+      groupedDates.push(group);
+      group = [dates[i]];
+    }
+  }
+
+  if (group.length > 0) {
+    groupedDates.push(group);
+  }
+
+  return groupedDates;
+}
+
+export function formatDateRange(dates: string[]): string {
+  if (dates.length === 1) {
+    return formatDate(dates[0], "d. MMMM");
+  }
+
+  const firstDate = toLocalTime(dates[0]);
+  const lastDate = toLocalTime(dates[dates.length - 1]);
+
+  if (firstDate.getMonth() === lastDate.getMonth()) {
+    // same month
+    return `${firstDate.getDay()}.-${lastDate.getDay()}. ${formatDate(
+      firstDate,
+      "MMMM"
+    )}`;
+  }
+
+  // continues into next month
+  const formattedFirstDate = formatDate(firstDate, "d. MMMM");
+  const formattedLastDate = formatDate(lastDate, "d. MMMM");
+  return `${formattedFirstDate} - ${formattedLastDate}`;
+}