add day of week

typed.go

@@ -77,3 +77,11 @@ func WithStaticDate(t time.Time) TimerOptions {
 		option.date = t
 	}
 }
+
+func NextDayOfWeek(date time.Time, weekDay int) time.Time {
+	sub := weekDay - int(date.Weekday())
+	if sub <= 0 {
+		sub += 7
+	}
+	return date.Add(time.Hour * 24 * time.Duration(sub))
+}