JavaScript function for the get the formatted date of tomorrow

Question

I need a JavaScript-function which always computes the date of the next day. Then returns the date as a string, formatted in the way: dd.mm.yyyy

I wrote this code:

const getDateStringForTomorrow = () => {
 const millisOfDay = 1000 * 60 * 60 * 24;
 const oTomorrow = new Date(Date.now() + millisOfDay);
 const day = ("0" + oTomorrow.getDate()).slice(-2);
 const month = ("0" + (oTomorrow.getMonth() + 1)).slice(-2);
 const year = oTomorrow.getFullYear();
 return `${day}.${month}.${year}`;
};
console.log(getDateStringForTomorrow());

Can I expect my function to work as expected and to provide correct results?

What't your opinion about the way I have written the function? To you think it's overly verbose?

• Scotty Jamison: Instead of adding a '0' and slicing, I might prefer .toString().padStart(2, '0') - I think it reads a little better.
• Scotty Jamison: Also, if accuracy matters, a day doesn't always have the same number of milliseconds (i.e. leap minutes). This would be an alternative way to get the next day: oTomorrow = new Date(); oTomorrow.setDate(oTomorrow.getDate() + 1) (setDate() will correctly handle too-large numbers)
• michael.zech: @Scotty Jamison I have seen the technique you are mentioning, in an article: flaviocopes.com/how-to-get-tomorrow-date-javascript Now, it becomes clear to me, why they are doing it that way. Thanks.

Answer 1

With Intl.DateTimeFormat you can also format the date elements to 2 and 4 digits. You code would then look something like this:

const getDateStringForTomorrow = () => {
 const tomorrow = new Date();
 tomorrow.setDate(tomorrow.getDate() + 1);
 const day = new Intl.DateTimeFormat('en', { day: '2-digit' }).format(tomorrow);
 const month = new Intl.DateTimeFormat('en', { month: '2-digit' }).format(tomorrow);
 const year = new Intl.DateTimeFormat('en', { year: 'numeric' }).format(tomorrow);
 return day + '.' + month + '.' + year;
};
console.log(getDateStringForTomorrow());

Another variant uses the European date format to get the order of the elements correctly and then only replaces dashes by dots:

const getDateStringForTomorrow = () => {
 const tomorrowDate = new Date();
 tomorrowDate.setDate(tomorrowDate.getDate() + 1);
 const tomorrowStr = new Intl.DateTimeFormat('uk', { day: '2-digit', month: '2-digit', year: 'numeric' }).format(tomorrow);
 return tomorrowStr.replaceAll('-','.');
};
console.log(getDateStringForTomorrow());

The advantage of using Intl.DateTimeFormat() is that it writes out very clearly what you want.