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Mastering Day of the Week Retrieval in JavaScript: A Comprehensive Guide

Getting the Day of the Week in JavaScript

Have you ever needed to know what day of the week a certain date falls on? Perhaps youre building a scheduling app, or maybe youre simply trying to find out if Friday falls on the 13th this month.

Either way, JavaScript provides a quick and easy way to get the day of the week for a given date. In this article, we will explore several different options for getting the day of the week in JavaScript, ranging from numerical to full name formats and even specifying locale.

Using Date Object Methods

The simplest way to get the day of the week in JavaScript is to use the built-in `Date` object. The `Date` object in JavaScript represents a specific moment in time and provides several methods to retrieve information about that moment.

The `getDay()` method returns the day of the week for a given date, where Sunday is 0 and Saturday is 6. Heres an example:

“`javascript

const date = new Date(“2022-08-23”);

const dayOfWeek = date.getDay(); // Returns 2 (Tuesday)

“`

Note that the `getDay()` method can only return the day of the week in numerical format.

Numerical Format

If you prefer to get the day of the week in numerical format, which is useful for indexing purposes, you can simply use the `getDay()` method as shown above. Heres an example of how to use the numerical format to check if a certain day falls on a weekend:

“`javascript

const date = new Date(“2022-08-13”); // Saturday the 13th

const dayOfWeek = date.getDay();

if (dayOfWeek === 0 || dayOfWeek === 6) {

console.log(“Weekend!”);

} else {

console.log(“Not a weekend.”);

}

“`

Full Name Format

If you prefer to get the day of the week in a more human-readable format, you can use the `toLocaleDateString()` method along with the Internationalization API to get the full name of the day of the week. Heres an example:

“`javascript

const date = new Date(“2022-08-23”);

const options = { weekday: ‘long’ };

const dayOfWeek = date.toLocaleDateString(‘en-EN’, options);

console.log(dayOfWeek); // “Tuesday”

“`

In this example, we pass the options object to `toLocaleDateString()`, which includes the `weekday: ‘long’` property.

This property specifies that we want the full name of the day of the week. We also pass the locale as the first argument to `toLocaleDateString()`, which in this case is `’en-EN’`, or English for users in England.

Specifying Locale

If you want to get the full name of the day of the week in a different language or locale, you can simply pass the appropriate locale code as the first argument to `toLocaleDateString()`. For example, if you want to get the full name of the day of the week in German, you can use the `’de-DE’` locale code like this:

“`javascript

const date = new Date(“2022-08-23”);

const options = { weekday: ‘long’ };

const dayOfWeek = date.toLocaleDateString(‘de-DE’, options);

console.log(dayOfWeek); // “Dienstag”

“`

In this example, we pass `’de-DE’` as the first argument to `toLocaleDateString()` to get the full name of the day of the week in German.

Reusable Function

If you need to get the day of the week in a specific format multiple times throughout your code, you may want to consider creating a reusable function. Heres an example of how to create a new method on the `Date` prototype called `getDayAsString()` that returns the full name of the day of the week:

“`javascript

Date.prototype.getDayAsString = function(locale, format) {

const options = { weekday: format };

return this.toLocaleDateString(locale, options);

}

const date = new Date(“2022-08-23”);

const dayOfWeek = date.getDayAsString(‘en-EN’, ‘long’);

console.log(dayOfWeek); // “Tuesday”

“`

In this example, we create a new method on the `Date` prototype called `getDayAsString()`, which takes two arguments: `locale` and `format`.

The `locale` argument specifies which locale to use, and the `format` argument specifies whether to return the full name of the day of the week (`’long’`), the short name (`’short’`), or the narrow name (`’narrow’`). This allows us to easily get the day of the week in whichever format we need throughout our code.

AuthorAs a software engineer and open-source contributor, Ive worked on a multitude of projects that involve date and time manipulation. Ive often found myself needing to get the day of the week for a given date, which is why I wrote this article to share some of the methods that Ive found useful.

You can follow me on Twitter @rlavarian to stay updated on my latest articles and projects. Guide to

Getting the Day of the Week in JavaScript: A Helpful Resource

Knowing what day of the week a certain date falls on can be useful for a variety of reasons.

Whether you’re building a scheduling app or simply curious about the day of the week for a specific date, JavaScript provides several methods for retrieving this information. In this guide, we explored several different options for getting the day of the week in JavaScript, ranging from numerical to full name formats and even specifying a locale.

We also included a section on creating a reusable function for getting the day of the week in a specific format.

Using Date Object Methods

The `Date` object in JavaScript provides several methods for working with dates, including the `getDay()` method, which returns the day of the week for a given date. This method returns an integer between 0 and 6, where Sunday is 0 and Saturday is 6.

While this format may be useful if you need to index days of the week, it can be difficult to read as a human-readable format.

Numerical Format

The numerical format can be useful if you need to use the day of the week for indexing. To use this format, simply call the `getDay()` method on a `Date` object, as shown in the previous section.

You can then use the returned integer to index an array or perform any other necessary actions.

Full Name Format

If you prefer a more human-readable format, you can use the `toLocaleDateString()` method along with the Internationalization API to get the full name of the day of the week. To do this, you need to specify the `weekday` property in the `options` object that you pass to `toLocaleDateString()`.

You can specify whether to return the full name, short name, or narrow name for the day of the week using the `long`, `short`, or `narrow` format values, respectively. Additionally, you can specify the locale you wish to use by passing the appropriate locale code as the first argument to `toLocaleDateString()`.

Specifying Locale

One of the more powerful features of the `toLocaleDateString()` method is the ability to specify a locale. This allows you to get the full name of the day of the week in a language other than English.

All you need to do is pass the appropriate locale code as the first argument to `toLocaleDateString()`. For example, if you want to get the full name of the day of the week in French, you can use the `’fr-FR’` locale code.

Reusable Function

If you need to get the day of the week in a specific format multiple times throughout your code, it can be helpful to create a reusable function. In this section, we explored how to create a new method on the `Date` prototype called `getDayAsString()` that returns the full name of the day of the week.

This method takes two arguments: `locale` and `format`. By creating a reusable function, you can save time and make your code more readable and maintainable.

Gratitude & Author’s Twitter

We hope that this guide has been helpful in explaining the different methods for getting the day of the week in JavaScript. Thanks for reading! If you have any feedback or suggestions for future articles, feel free to tweet us at @rlavarian.

We love hearing from our readers and we want to create content that truly helps and inspires you. In summary, this guide presented various methods to get the day of the week in JavaScript, including the numerical and full name format as well as specifying locale.

Additionally, creating a reusable function was discussed as an option to make the code more efficient. Knowing the day of the week can be important for a variety of reasons such as scheduling, planning, or simply keeping track of dates.

This article emphasizes the importance of having a clear understanding of the methods available and being able to use them effectively. Whether you’re a beginner or an experienced developer, mastering these skills can make your code more efficient and readable.

Thanks for reading, and keep practicing!

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