Fix case for no previous bleeding day. Use new getCycleDay API

get-cycle-day-number.js

@@ -4,15 +4,10 @@ const LocalDate = joda.LocalDate
 
 export default function config(bleedingDaysSortedByDateView, opts) {
   opts = opts || {
-    // at the very minimum, a cycle can be a bleeding day
-    // followed by a non-bleeding day, thus a length of 2
     maxBreakInBleeding: 1
   }
 
   return function getCycleDayNumber(targetDateString) {
-    // sort the cycle days in descending order so we travel into
-    // the past as we iterate over the array
-    // also, to retrieve the number, we only need the cycle days before the target day
     const targetDate = LocalDate.parse(targetDateString)
     const withWrappedDates = bleedingDaysSortedByDateView
       .filter(day => !day.bleeding.exclude)
@@ -20,16 +15,15 @@ export default function config(bleedingDaysSortedByDateView, opts) {
         day.wrappedDate = LocalDate.parse(day.date)
         return day
       })
-    // TODO write test for what if there is no first day before?? aka no firstbleedingdaybeforeindex
+
     const firstBleedingDayBeforeTargetDayIndex = withWrappedDates.findIndex(day => day.wrappedDate.isBefore(targetDate))
-    const cycleDays = withWrappedDates.slice(firstBleedingDayBeforeTargetDayIndex)
+    if (firstBleedingDayBeforeTargetDayIndex < 0) return null
+    const previousBleedingDays = withWrappedDates.slice(firstBleedingDayBeforeTargetDayIndex)
 
-    const lastPeriodStart = cycleDays.find((day, i) => {
-      return thereIsNoPreviousBleedingDayWithinTheThreshold(day, cycleDays.slice(i + 1), opts.maxBreakInBleeding)
+    const lastPeriodStart = previousBleedingDays.find((day, i) => {
+      return thereIsNoPreviousBleedingDayWithinTheThreshold(day, previousBleedingDays.slice(i + 1), opts.maxBreakInBleeding)
     })
 
-    if (!lastPeriodStart) return null
-
     const diffInDays = lastPeriodStart.wrappedDate.until(targetDate, joda.ChronoUnit.DAYS)
 
     // cycle starts at day 1