Solve exercise meetup

Author: programmiri

meetup/meetup.js

@@ -0,0 +1,73 @@
+const weekdays = [
+	'Sunday',
+	'Monday',
+	'Tuesday',
+	'Wednesday',
+	'Thursday',
+	'Friday',
+	'Saturday',
+];
+
+const teenthDays = [13, 14, 15, 16, 17, 18, 19];
+
+function getWeekday(date) {
+	return weekdays[date.getDay()];
+}
+
+function daysBetween(startDay, endDay) {
+	const number = weekdays.indexOf(endDay) - weekdays.indexOf(startDay);
+	if (number < 0) {
+		return 7 + number;
+	}
+	return number;
+}
+
+function getXte(year, month, dayName, multiplicator) {
+	const firstDayOfMonth = getWeekday(new Date(year, month, 1));
+	const daysFromStartToFirstWeekday = daysBetween(firstDayOfMonth, dayName);
+
+	const days = 1 + daysFromStartToFirstWeekday + 7 * multiplicator;
+	return new Date(year, month, days);
+}
+
+function getLast(year, month, dayName) {
+	const lastDayOfMonth = getWeekday(new Date(year, month + 1, 0));
+	const daysInMonth = new Date(year, month + 1, 0).getDate();
+	const daysFromEndToWeekday = daysBetween(dayName, lastDayOfMonth);
+
+	const days = daysInMonth - daysFromEndToWeekday;
+	return new Date(year, month, days);
+}
+
+function getTeenth(year, month, dayName) {
+	const day = teenthDays.filter((num) => {
+		const weekDayToCheck = getWeekday(new Date(year, month, num));
+		return dayName === weekDayToCheck;
+	});
+
+	return new Date(year, month, day);
+}
+
+const dateCalcMap = [
+	{ type: '1st', multiplicator: 0, func: getXte },
+	{ type: '2nd', multiplicator: 1, func: getXte },
+	{ type: '3rd', multiplicator: 2, func: getXte },
+	{ type: '4th', multiplicator: 3, func: getXte },
+	{ type: '5th', multiplicator: 4, func: getXte },
+	{ type: 'last', multiplicator: 0, func: getLast },
+	{ type: 'teenth', number: 1, func: getTeenth },
+];
+
+export function meetupDay(year, month, dayName, type) {
+	const currDateCalc = dateCalcMap.find((entry) => entry.type === type);
+	const meetupDate = currDateCalc.func(
+		year,
+		month,
+		dayName,
+		currDateCalc.multiplicator
+	);
+	if (meetupDate.getMonth() !== month) {
+		throw new Error();
+	}
+	return meetupDate;
+}

meetup/meetup.spec.js

@@ -2,54 +2,66 @@ import { meetupDay } from './meetup';
 
 describe('meetupDay()', () => {
   test('test monteenth of may 2013', () => {
-    expect(meetupDay(2013, 4, 'Monday', 'teenth')).toEqual(new Date(2013, 4, 13));
+    expect(meetupDay(2013, 4, 'Monday', 'teenth')).toEqual(
+      new Date(2013, 4, 13)
+    );
   });
 
-  xtest('test saturteenth of february 2013', () => {
-    expect(meetupDay(2013, 1, 'Saturday', 'teenth')).toEqual(new Date(2013, 1, 16));
+  test('test saturteenth of february 2013', () => {
+    expect(meetupDay(2013, 1, 'Saturday', 'teenth')).toEqual(
+      new Date(2013, 1, 16)
+    );
   });
 
-  xtest('test first tuesday of may 2013', () => {
+  test('test first tuesday of may 2013', () => {
     expect(meetupDay(2013, 4, 'Tuesday', '1st')).toEqual(new Date(2013, 4, 7));
   });
 
-  xtest('test second monday of april 2013', () => {
+  test('test second monday of april 2013', () => {
     expect(meetupDay(2013, 3, 'Monday', '2nd')).toEqual(new Date(2013, 3, 8));
   });
 
-  xtest('test third thursday of september 2013', () => {
-    expect(meetupDay(2013, 8, 'Thursday', '3rd')).toEqual(new Date(2013, 8, 19));
+  test('test third thursday of september 2013', () => {
+    expect(meetupDay(2013, 8, 'Thursday', '3rd')).toEqual(
+      new Date(2013, 8, 19)
+    );
   });
 
-  xtest('test fourth sunday of march 2013', () => {
+  test('test fourth sunday of march 2013', () => {
     expect(meetupDay(2013, 2, 'Sunday', '4th')).toEqual(new Date(2013, 2, 24));
   });
 
-  xtest('test last thursday of october 2013', () => {
-    expect(meetupDay(2013, 9, 'Thursday', 'last')).toEqual(new Date(2013, 9, 31));
+  test('test last thursday of october 2013', () => {
+    expect(meetupDay(2013, 9, 'Thursday', 'last')).toEqual(
+      new Date(2013, 9, 31)
+    );
   });
 
-  xtest('test last wednesday of february 2012', () => {
-    expect(meetupDay(2012, 1, 'Wednesday', 'last')).toEqual(new Date(2012, 1, 29));
+  test('test last wednesday of february 2012', () => {
+    expect(meetupDay(2012, 1, 'Wednesday', 'last')).toEqual(
+      new Date(2012, 1, 29)
+    );
   });
 
-  xtest('test last wednesday of december 2014', () => {
-    expect(meetupDay(2014, 11, 'Wednesday', 'last')).toEqual(new Date(2014, 11, 31));
+  test('test last wednesday of december 2014', () => {
+    expect(meetupDay(2014, 11, 'Wednesday', 'last')).toEqual(
+      new Date(2014, 11, 31)
+    );
   });
 
-  xtest('test last sunday of only four week february 2015', () => {
+  test('test last sunday of only four week february 2015', () => {
     expect(meetupDay(2015, 1, 'Sunday', 'last')).toEqual(new Date(2015, 1, 22));
   });
 
-  xtest('test first friday of december 2012', () => {
+  test('test first friday of december 2012', () => {
     expect(meetupDay(2012, 11, 'Friday', '1st')).toEqual(new Date(2012, 11, 7));
   });
 
-  xtest('test fifth monday of march 2015', () => {
+  test('test fifth monday of march 2015', () => {
     expect(meetupDay(2015, 2, 'Monday', '5th')).toEqual(new Date(2015, 2, 30));
   });
 
-  xtest('test nonexistent fifth monday of february 2015', () => {
+  test('test nonexistent fifth monday of february 2015', () => {
     expect(() => {
       meetupDay(2015, 1, 'Monday', '5th');
     }).toThrow();