Add lastDayOfMonth support

src/code-sandbox.json

@@ -61,6 +61,7 @@
   "date-fns/08-month/getMonth": "https://codesandbox.io/s/jqquk?previewwindow=tests&file=/08-month/getMonth/vanilla.js",
   "date-fns/08-month/isFirstDayOfMonth": "https://codesandbox.io/s/ltltp?previewwindow=tests&file=/08-month/isFirstDayOfMonth/vanilla.js",
   "date-fns/08-month/isLastDayOfMonth": "https://codesandbox.io/s/d9veq?previewwindow=tests&file=/08-month/isLastDayOfMonth/vanilla.js",
+  "date-fns/08-month/lastDayOfMonth": "https://codesandbox.io/s/date-fns-lastdayofmonth-eun1ls?previewwindow=tests&file=/00-generic/compareDesc/vanilla.js",
   "date-fns/08-month/isSameMonth": "https://codesandbox.io/s/04clz?previewwindow=tests&file=/08-month/isSameMonth/vanilla.js",
   "date-fns/08-month/isThisMonth": "https://codesandbox.io/s/4u126?previewwindow=tests&file=/08-month/isThisMonth/vanilla.js",
   "date-fns/08-month/setMonth": "https://codesandbox.io/s/jcvuk?previewwindow=tests&file=/08-month/setMonth/vanilla.js",

src/content/date-fns/08-month/lastDayOfMonth/date-fns.js

@@ -0,0 +1,6 @@
+// https://date-fns.org/v2.29.3/docs/lastDayOfMonth
+const lastDayOfMonth = require('date-fns/lastDayOfMonth')
+
+// Get the last day of a month.
+module.exports = lastDayOfMonth(new Date(2014, 1, 25)).toDateString()
+// => Fri Feb 28 2014

src/content/date-fns/08-month/lastDayOfMonth/notes.md

@@ -0,0 +1 @@
+Get the last day of a month from date.

src/content/date-fns/08-month/lastDayOfMonth/spec.js

@@ -0,0 +1,9 @@
+const expected = 'Fri Feb 28 2014'
+
+const datefns = require('./date-fns')
+const plain = require('./vanilla')
+
+test('lastDayOfMonth', () => {
+  expect(datefns).toEqual(expected)
+  expect(plain).toEqual(datefns)
+})

src/content/date-fns/08-month/lastDayOfMonth/vanilla.js

@@ -0,0 +1,13 @@
+function lastDayOfMonth(date) {
+  const dateClone = new Date(date.getTime())
+  const month = dateClone.getMonth()
+  dateClone.setDate(1)
+  dateClone.setMonth(month + 1)
+  dateClone.setDate(0)
+
+  return dateClone
+}
+
+// Get the last day of a month.
+module.exports = lastDayOfMonth(new Date(2014, 1, 25)).toDateString()
+// => Fri Feb 28 2014