Get cycle day for day in any cycle, not just the current

get-cycle-day-number.js

@@ -10,7 +10,11 @@ export default function config(opts) {
   return function getCycleDayNumber(unsorted, targetDate) {
     // sort the cycle days in descending order so we travel into
     // the past as we iterate over the array
-    const cycleDays = [...unsorted].sort((a, b) => b.date.isAfter(a.date))
+    // also, to retrieve the number, we only need the cycle days before the target day
+    // TODO we can probably rely on the db to do the sorting for us
+    const sorted = [...unsorted].sort((a, b) => b.date.isAfter(a.date))
+    const firstDayBeforeTargetDayIndex = sorted.findIndex(day => day.date.isBefore(targetDate))
+    const cycleDays = sorted.slice(firstDayBeforeTargetDayIndex)
 
     const lastPeriodStart = cycleDays.find((day, i) => {
       if (

test/get-cycle-day.spec.js

@@ -142,6 +142,35 @@ describe('getCycleDay', () => {
     const result = getCycleDayNumber(cycleDays, targetDate)
     expect(result).to.eql(15)
   })
+
+  it('gets the correct number if the target day is not in the current cycle', () => {
+    const cycleDays = [{
+      date: moment([2018, 5, 14]),
+    }, {
+      date: moment([2018, 5, 13]),
+      bleeding: {
+        value: 2
+      }
+    }, {
+      date: moment([2018, 4, 12]),
+    }, {
+      date: moment([2018, 4, 11]),
+      bleeding: {
+        value: 2
+      }
+    }, {
+      date: moment([2018, 4, 10]),
+      bleeding: {
+        value: 2
+      }
+    }, {
+      date: moment([2018, 4, 9]),
+    }]
+
+    const targetDate = moment([2018, 4, 27])
+    const result = getCycleDayNumber(cycleDays, targetDate)
+    expect(result).to.eql(18)
+  })
 })
 
 describe('getCycleDay returns null', () => {