Getting tomorrow and day after tomorrow date in JavaScript

Using the Date class in JavaScript, we can easily calculate tomorrow and the day after tomorrow from the current date. The new Date() constructor returns a JavaScript Date object for the current day.

Getting Today's Date

First, let's get today's date using the Date constructor:

const today = new Date();
console.log("Today:", today.toDateString());

Today: Thu Aug 13 2020

Method 1: Using setDate() with Date Copying

We can create new Date objects by copying today's date and then adding days using the setDate() method:

// Getting today's date
const today = new Date();

// Creating tomorrow by copying today and adding 1 day
const tomorrow = new Date(today);
tomorrow.setDate(tomorrow.getDate() + 1);

// Creating day after tomorrow by copying today and adding 2 days
const dayAfterTomorrow = new Date(today);
dayAfterTomorrow.setDate(dayAfterTomorrow.getDate() + 2);

console.log("Today:", today.toDateString());
console.log("Tomorrow:", tomorrow.toDateString());
console.log("Day after tomorrow:", dayAfterTomorrow.toDateString());

Today: Thu Aug 13 2020
Tomorrow: Fri Aug 14 2020
Day after tomorrow: Sat Aug 15 2020

Method 2: Using Milliseconds

Another approach is to add milliseconds to the current date. One day equals 24 hours × 60 minutes × 60 seconds × 1000 milliseconds:

const today = new Date();
const oneDayInMs = 24 * 60 * 60 * 1000; // milliseconds in a day

const tomorrow = new Date(today.getTime() + oneDayInMs);
const dayAfterTomorrow = new Date(today.getTime() + (2 * oneDayInMs));

console.log("Today:", today.toDateString());
console.log("Tomorrow:", tomorrow.toDateString());
console.log("Day after tomorrow:", dayAfterTomorrow.toDateString());

Today: Thu Aug 13 2020
Tomorrow: Fri Aug 14 2020
Day after tomorrow: Sat Aug 15 2020

How setDate() Handles Month Boundaries

The setDate() method automatically handles month and year boundaries. If adding days exceeds the current month, it rolls over to the next month:

// Example with month boundary
const endOfMonth = new Date(2023, 7, 31); // August 31, 2023
const nextDay = new Date(endOfMonth);
nextDay.setDate(nextDay.getDate() + 1);

console.log("End of month:", endOfMonth.toDateString());
console.log("Next day:", nextDay.toDateString()); // Automatically becomes September 1

End of month: Thu Aug 31 2023
Next day: Fri Sep 01 2023

Comparison

Conclusion

The setDate() method is the recommended approach for calculating future dates as it automatically handles month boundaries and leap years. Both methods work reliably for simple date arithmetic in JavaScript.