Don't do duplicate work in getLastMensesStart

lib/cycle.js

@@ -26,70 +26,49 @@ export default function config(opts) {
     minCyclesForPrediction = opts.minCyclesForPrediction || 3
   }
 
-  function getLastMensesStart(targetDateString) {
-    const targetDate = LocalDate.parse(targetDateString)
-    const withWrappedDates = bleedingDaysSortedByDate
-      .filter(day => !day.bleeding.exclude)
-      .map(day => {
-        day.wrappedDate = LocalDate.parse(day.date)
-        return day
-      })
+  function findLatestMensesStart(bleedingDays) {
+    if (!bleedingDays.length) return null
 
-    // the index of the first bleeding day before the target day
-    const index = withWrappedDates.findIndex(day => {
-      return (
-        day.wrappedDate.isEqual(targetDate) ||
-        day.wrappedDate.isBefore(targetDate)
-      )
-    })
-
-    if (index < 0) {
-      withWrappedDates.forEach(day => delete day.wrappedDate)
-      return null
-    }
-
-    const prevBleedingDays = withWrappedDates.slice(index)
-
-    const lastMensesStart = prevBleedingDays.find((day, i) => {
-      return noBleedingDayWithinThreshold(day, prevBleedingDays.slice(i + 1))
+    // assumes bleeding days are ordered latest first, and
+    // excluded values already removed
+    const lastMensesStart = bleedingDays.find((day, i) => {
+      return noBleedingDayWithinThreshold(day, bleedingDays.slice(i + 1))
     })
 
     function noBleedingDayWithinThreshold(day, previousBleedingDays) {
-      const periodThreshold = day.wrappedDate.minusDays(maxBreakInBleeding + 1)
-      return !previousBleedingDays.some(({ wrappedDate }) => {
-        return (
-          wrappedDate.equals(periodThreshold) ||
-          wrappedDate.isAfter(periodThreshold)
-        )
-      })
+      const localDate = LocalDate.parse(day.date)
+      const threshold = localDate.minusDays(maxBreakInBleeding + 1).toString()
+      return !previousBleedingDays.some(({ date }) => date >= threshold)
     }
 
-    withWrappedDates.forEach(day => delete day.wrappedDate)
     return lastMensesStart
   }
 
-  function getFollowingMensesStart(targetDateString) {
-    const targetDate = LocalDate.parse(targetDateString)
-    const withWrappedDates = bleedingDaysSortedByDate
+  function getLastMensesStartForDay(targetDateString) {
+    // the index of the first bleeding day before the target day
+    const index = bleedingDaysSortedByDate.findIndex(day => {
+      return day.date <= targetDateString && !day.bleeding.exclude
+    })
+
+    if (index < 0) return null
+
+    const prevBleedingDays = bleedingDaysSortedByDate.slice(index)
+    return findLatestMensesStart(prevBleedingDays)
+  }
+
+  function getFollowingMensesStartForDay(targetDateString) {
+    const followingBleedingDays = bleedingDaysSortedByDate
       .filter(day => !day.bleeding.exclude)
-      .map(day => {
-        day.wrappedDate = LocalDate.parse(day.date)
-        return day
-      })
-
-    const firstBleedingDayAfterTargetDay = withWrappedDates
       .reverse()
-      .find(day => {
-        return day.wrappedDate.isAfter(targetDate)
-      })
 
-    withWrappedDates.forEach(day => delete day.wrappedDate)
+    const firstBleedingDayAfterTargetDay = followingBleedingDays
+      .find(day => day.date > targetDateString)
 
     return firstBleedingDayAfterTargetDay
   }
 
   function getCycleDayNumber(targetDateString) {
-    const lastMensesStart = getLastMensesStart(targetDateString)
+    const lastMensesStart = getLastMensesStartForDay(targetDateString)
     if (!lastMensesStart) return null
     const targetDate = LocalDate.parse(targetDateString)
     const lastMensesLocalDate = LocalDate.parse(lastMensesStart.date)
@@ -111,7 +90,7 @@ export default function config(opts) {
   }
 
   function getPreviousCycle(dateString) {
-    const startOfCycle = getLastMensesStart(dateString)
+    const startOfCycle = getLastMensesStartForDay(dateString)
     if (!startOfCycle) return null
     const dateBeforeStartOfCycle = LocalDate
       .parse(startOfCycle.date)
@@ -123,10 +102,10 @@ export default function config(opts) {
 
   function getCycleForDay(dayOrDate) {
     const dateString = typeof dayOrDate === 'string' ? dayOrDate : dayOrDate.date
-    const cycleStart = getLastMensesStart(dateString)
+    const cycleStart = getLastMensesStartForDay(dateString)
     if (!cycleStart) return null
     const cycleStartIndex = cycleDaysSortedByDate.indexOf(cycleStart)
-    const nextMensesStart = getFollowingMensesStart(dateString)
+    const nextMensesStart = getFollowingMensesStartForDay(dateString)
     if (nextMensesStart) {
       return cycleDaysSortedByDate.slice(
         cycleDaysSortedByDate.indexOf(nextMensesStart) + 1,
@@ -137,16 +116,20 @@ export default function config(opts) {
     }
   }
 
-  function getAllMensesStarts(day, collectedDates) {
-    day = day || LocalDate.now().toString()
+  function getAllMensesStarts(initialBleedingDays = bleedingDaysSortedByDate) {
+    return recurse(initialBleedingDays.filter(d => !d.bleeding.exclude))
+
+    function recurse(bleedingDays, collectedDates) {
       collectedDates = collectedDates || []
-    const lastStart = getLastMensesStart(day)
+      const lastStart = findLatestMensesStart(bleedingDays)
       if (!lastStart) {
         return collectedDates
       } else {
-      const newDay = LocalDate.parse(lastStart.date).minusDays(1).toString()
         collectedDates.push(lastStart.date)
-      return getAllMensesStarts(newDay, collectedDates)
+        const index = bleedingDays.indexOf(lastStart)
+        const remainingDays = bleedingDays.slice(index + 1)
+        return recurse(remainingDays, collectedDates)
+      }
     }
   }
 

test/cycle.spec.js

@@ -625,7 +625,8 @@ describe('getAllMensesStart', () => {
     const result = getAllMensesStarts()
     expect(result.length).to.eql(2)
     expect(result).to.eql(['2018-06-01', '2018-05-01'])
-  }),
+  })
+
   it('works for two cycle starts with excluded data', () => {
     const cycleDaysSortedByDate = [
       {
@@ -649,7 +650,8 @@ describe('getAllMensesStart', () => {
     const result = getAllMensesStarts()
     expect(result.length).to.eql(2)
     expect(result).to.eql(['2018-06-01', '2018-05-01'])
-  }),
+  })
+
   it('returns an empty array if no bleeding days are given', () => {
     const cycleDaysSortedByDate = [ {} ]