We can use the getDate method to get the number of days in a month with JavaScript.
For instance, we can write:
const numDays = (y, m) => new Date(y, m, 0).getDate();
console.log(numDays(2020, 2));
We call the Date constructor with the y year, m month, and day 0 to create the Date instance with the last date of the given month.
Then we call getDate to get the value of the last day of the month m — 1according to the calendar.
Therefore, the console log should log 29 since February 2020 has 29 days.
Determine the Number of Days in a Month with moment.js
Also, we can use the daysInMonth method that comes with momenbt.js to get the number of days in a month.
For instance, we can write:
const numDays = moment("2020-02", "YYYY-MM").daysInMonth()
console.log(numDays);
to parse the year and month with the moment function into a moment object.
Then we call daysInMonth to get the number of days in the month for the given month.
So numDays is 29.
