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Table of Contents
Creating Date Objects
Getting and Setting Date Values
Formatting Dates for Display
Time Zones and UTC
Home Web Front-end JS Tutorial Working with Dates in JavaScript: A Complete Guide

Working with Dates in JavaScript: A Complete Guide

Jul 23, 2025 am 03:59 AM
date

JavaScript's date processing requires attention to creating, getting set values, formatting and time zone issues. 1. Create a Date object by using no parameters, timestamps, date strings or components; note that the month starts at 0 and the browser parsing strings may be inconsistent. 2. Use getDate, setDate and other methods to get/set the value, and use getTime() to compare dates. 3. Intl.DateTimeFormat can be used to ensure consistency, and third-party libraries can also be used. 4. UTC method should be used to deal with time zones to avoid confusion. The sending server recommends using UTC and backend conversion.

Working with Dates in JavaScript: A Complete Guide

Handling dates in JavaScript can be a bit tricky, especially if you're new to the language or coming from another programming background. The built-in Date object is powerful but has some quirks that can trip you up if you're not careful. In this guide, we'll walk through the most common use cases and best practices when working with dates in JavaScript.

Working with Dates in JavaScript: A Complete Guide

Creating Date Objects

The first thing you'll do when working with dates is create a Date object. There are several ways to do this:

  • Using no arguments: new Date() gives you the current date and time.
  • Using a timestamp: new Date(1630000000000) creates a specific moment based on million seconds since January 1, 1970.
  • Using a date string: new Date('2023-08-25') parses the string into a date object.
  • Using individual components: new Date(2023, 7, 25, 14, 30, 0) for year, month (zero-indexed!), day, hours, minutes, and seconds.

One important note: months are zero-based in JavaScript. So new Date(2023, 0, 1) actually refer to January 1st, not February.

Working with Dates in JavaScript: A Complete Guide

Also, be cautious with date strings — different browsers may parse them inconsistently, especially formats like '08/25/2023' .

Getting and Setting Date Values

Once you have a Date object, you'll often need to extract or modify parts of it. Here are some commonly used methods:

Working with Dates in JavaScript: A Complete Guide
  • getDate() / setDate() : Get or set the day of the month.
  • getMonth() / setMonth() : Remember again, months are zero-based.
  • getFullYear() / setFullYear() : For year values.
  • getHours() , getMinutes() , getSeconds() , etc.: For time components.

If you want to compare two dates, don't use === . Instead, compare their timestamps using .getTime() or Date.parse() .

For example:

 const d1 = new Date('2023-08-25');
const d2 = new Date('2023-08-25');

console.log(d1 === d2); // false
console.log(d1.getTime() === d2.getTime()); // true

Formatting Dates for Display

JavaScript doesn't provide a built-in way to format dates nicely out of the box, unless you're OK with browser-dependent outputs like toString() or toLocaleString() .

But here's a more reliable method:

Use Intl.DateTimeFormat which is part of the Internationalization API and allows locale-aware formatting.

Example:

 const date = new Date('2023-08-25');

const formatter = new Intl.DateTimeFormat('en-US', {
  year: 'numeric',
  month: 'long',
  day: 'numeric'
});

console.log(formatter.format(date)); // "August 25, 2023"

This gives you fine-grained control over how the date appears across different languages and regions.

Alternatively, many developers reach for libraries like date-fns or Luxon for more advanced formatting and manipulation needs.

Time Zones and UTC

JavaScript's Date object works internally in UTC, but by default displays in the local time zone of the system it's running on. This can lead to confusion if you're expecting consistent timezone behavior.

To avoid issues:

  • Use .getUTCDate() , .getUTCMonth() , etc., when you want to work strictly in UTC.
  • Be aware that methods like .toISOString() return UTC time in ISO format.
  • When sending dates to a server, it's usually safe to send them in UTC and handle conversion on the backend or at display time.

For complex timezone handling (like converting between time zones), consider using a library like Luxon or dayjs .


That's the core of working with dates in JavaScript. You can go a long way just by understanding these basics — even though the built-in Date object isn't perfect, knowing its behaviors and limitations helps avoid a lot of headaches.

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