Sometimes, we want to get list of days in a month with JavaScript.

In this article, we’ll look at how to get list of days in a month with JavaScript.

How to get list of days in a month with JavaScript?

To get list of days in a month with JavaScript, we can use the Date constructor and a while loop.

For instance, we write:

const getDaysArray = (year, month) => {
  const monthIndex = month - 1;
  const names = ['sun', 'mon', 'tue', 'wed', 'thu', 'fri', 'sat'];
  const date = new Date(year, monthIndex, 1);
  const result = [];
  while (date.getMonth() === monthIndex) {
    result.push(date.getDate() + '-' + names[date.getDay()]);
    date.setDate(date.getDate() + 1);
  }
  return result;
}

console.log(getDaysArray(2020, 5))

We create the getDaysArray function that takes the year and month as parameters.

Then we subtract month by 1 and assign that to monthIndex to make sure the months are between 0 and 11 as required by the Date constructor.

Next, we create the names array with the days of the week.

And then we create the first date with the Date constructor.

We then create the result array to store the results.

Next, we create a while loop to check if date.getMonth returns the same value as monthIndex.

If it’s not then date is a date in the next month, so we end the loop.

In the loop body, we call result.push to push the result into the result array.

And the we call date.setDate to change date to the next day.

Finally, we return the results.

Therefore, we get:

 ['1-fri', '2-sat', '3-sun', '4-mon', '5-tue', '6-wed', '7-thu', '8-fri', '9-sat', '10-sun', '11-mon', '12-tue', '13-wed', '14-thu', '15-fri', '16-sat', '17-sun', '18-mon', '19-tue', '20-wed', '21-thu', '22-fri', '23-sat', '24-sun', '25-mon', '26-tue', '27-wed', '28-thu', '29-fri', '30-sat', '31-sun']

from the console log.

Conclusion

To get list of days in a month with JavaScript, we can use the Date constructor and a while loop.