Merged in feat/LOY-423-Nights-Stayed-Progress-for-L6-Members (pull request #3360)

feat(LOY-423): Add progress bar for L6 members showing nights stayed

* feat(LOY-423): Add progress bar for L6 members showing nights stayed

* chore(LOY-423): shorten css selector


Approved-by: Matilda Landström

apps/scandic-web/utils/getTierStartDate.ts

@@ -0,0 +1,14 @@
+/**
+ * Calculate the tier start date from the tier expiration date.
+ * The tier period is 1 year, so start date is expiration minus 1 year.
+ */
+export function getTierStartDate(
+  tierExpirationDate: string | null | undefined
+): string | null {
+  if (!tierExpirationDate) return null
+
+  const date = new Date(tierExpirationDate)
+  date.setFullYear(date.getFullYear() - 1)
+
+  return date.toISOString().split("T")[0]
+}