Merge pull request #1810 from shanyuhai123/feature/getMonthDays

Add snippet for getMonthDays

snippets/daysInMonth.md

@@ -0,0 +1,20 @@
+---
+title: daysInMonth
+tags: date,beginner
+firstSeen: 2021-06-13T05:00:00-04:00
+---
+
+Gets the number of days in the given `month` of the specified `year`.
+
+- Use the `new Date()` constructor to create a date from the given `year` and `month`.
+- Set the days parameter to `0` to get the last day of the previous month, as months are zero-indexed.
+- Use `Date.prototype.getDate()` to return the number of days in the given `month`. 
+
+```js
+const daysInMonth = (year, month) => new Date(year, month, 0).getDate();
+```
+
+```js
+daysInMonth(2020, 12)); // 31
+daysInMonth(2024, 2)); // 29
+```