Fixes the issue where a full next week was tacked on when the next mo…

…nth began at the beginning of the week

src/utils/getCalendarMonthWeeks.js

@@ -24,13 +24,17 @@ export default function getCalendarMonthWeeks(month, enableOutsideDays) {
     }
   }
 
-  // days belonging to the next month
-  for (let k = currentDay.weekday(), count = 0; k < 7; k++, count++) {
-    const nextDay = enableOutsideDays && currentDay.clone().add(count, 'day');
-    currentWeek.push(nextDay);
-  }
+  // weekday() returns the index of the day of the week according to the locale
+  // this means if the week starts on Monday, weekday() will return 0 for a Monday date, not 1
+  if (currentDay.weekday() !== 0) {
+    // days belonging to the next month
+    for (let k = currentDay.weekday(), count = 0; k < 7; k++, count++) {
+      const nextDay = enableOutsideDays && currentDay.clone().add(count, 'day');
+      currentWeek.push(nextDay);
+    }
 
-  weeksInMonth.push(currentWeek);
+    weeksInMonth.push(currentWeek);
+  }
 
   return weeksInMonth;
 }

test/utils/getCalendarMonthWeeks_spec.js

@@ -55,13 +55,41 @@ describe('getCalendarMonthWeeks', () => {
       expect(containsFirstOfMonth).to.equal(true);
     });
 
-    it('contains last of the month', () => {
+    it('last week contains last of the month', () => {
       const lastOfMonth = today.clone().endOf('month');
       const containsLastOfMonth = weeks[weeksWithOutsideDays.length - 1]
         .filter(day => lastOfMonth.isSame(day, 'day')).length > 0;
       expect(containsLastOfMonth).to.equal(true);
     });
 
+    it('last week contains last of the month if next month begins on Sunday', () => {
+      const december2016 = moment('2016-12-01');
+      const lastOfMonth = december2016.clone().endOf('month');
+      const weeksInDecember = getCalendarMonthWeeks(december2016);
+      const containsLastOfMonth = weeksInDecember[weeksInDecember.length - 1]
+        .filter(day => lastOfMonth.isSame(day, 'day')).length > 0;
+      expect(containsLastOfMonth).to.equal(true);
+    });
+
+    it('last week contains last of the month if next month begins on Monday', () => {
+      moment.locale('es');
+      const april2017 = moment('2017-04-01');
+      const lastOfMonth = april2017.clone().endOf('month');
+      const weeksInApril = getCalendarMonthWeeks(april2017);
+      const containsLastOfMonth = weeksInApril[weeksInApril.length - 1]
+        .filter(day => lastOfMonth.isSame(day, 'day')).length > 0;
+      expect(containsLastOfMonth).to.equal(true);
+    });
+
+    it('last week contains last of the month if next month begins on Saturday', () => {
+      const september2016 = moment('2016-09-01');
+      const lastOfMonth = september2016.clone().endOf('month');
+      const weeksInSeptember = getCalendarMonthWeeks(september2016);
+      const containsLastOfMonth = weeksInSeptember[weeksInSeptember.length - 1]
+        .filter(day => lastOfMonth.isSame(day, 'day')).length > 0;
+      expect(containsLastOfMonth).to.equal(true);
+    });
+
     it('each week has 7 non-null elements', () => {
       const hasNoNullElements = weeksWithOutsideDays
         .reduce((w1, w2) => w1 && w2.reduce((d1, d2) => d1 && !!d2, true), true);