Get first and last date of current month with JavaScript or jQuery

Deal with edge cases in date handling

JavaScript's Date object is a powerful tool, but careful handling is needed for edge cases:

• Use setFullYear() when setting the year to avoid misinterpretation of two-digit years.
• Timezones can alter date results. Use .toISOString() or .toLocaleDateString() for consistent date representation.
• Keep in mind that JavaScript counts months from 0. January is 0 and December is 11 - yes, JavaScript starts counting from zero, just like arrays!

Dealing with other months

For the date boundaries of any given month, adapt the initial function like so:

function getMonthBoundaries(year, month) {
  // "Peeking inside a new month..."
  const firstDay = new Date(year, month, 1); 
  // "...and we've reached the exit!" 
  const lastDay = new Date(year, month + 1, 0); 
  return { firstDay, lastDay };
}
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Just call getMonthBoundaries(yourYear, yourMonth) to receive the boundaries of your choice.

Show off your dates in style

To display dates in the popular MM/DD/YYYY style:

function formatDate(date) {
  // "Hey there, I'm a single digit. Got any spare zeros?" - Single digit day
  let day = ('0' + date.getDate()).slice(-2); 
  // "Could use some padding. It's cold out there!" - Single digit month
  let month = ('0' + (date.getMonth() + 1)).slice(-2); 
  let year = date.getFullYear();
  return month + '/' + day + '/' + year;
}
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This snippet adds zeros to single-digit days and months, keeping date formatting consistent.

Better dating with Datejs

Date manipulations are quick and easy with the Datejs library:

// "Date.today() - It's carpe diem time!"
const now = Date.today(); 
// "Excuse me! Trying to get to the start here!" - First day of the month
const firstDay = now.moveToFirstDayOfMonth(); 
// "Fast-forward to the last day, please!" - Last day of the month
const lastDay = now.moveToLastDayOfMonth(); 
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Format these dates using toString("MM/dd/yyyy") for added flair.

Are timezones interrupting your dates?

To get accurate dates irrespective of timezones, set the date to the start of the day in your local timezone:

const date = new Date();
// "Zero it out to blend in with the locals!" - Aligns the date to the start of the day
date.setHours(0,0,0,0);
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