How to Get Day of Week in JavaScript?

While learning JavaScript you might have stumbled across how to get name of the week day e.g. “Sunday” “Monday” etc from a date. In this article we will learn to get the day name of the week in short and long format.

Date API 💻

JavaScript date api provides getDay() method to get the week day index of a date instance. It returns a zero based integer from 0-6 specifying the day of week for the given date.

• 0 means Sunday
• 1 means Monday and so on.

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let date = new Date("2021-07-06T11:24:49.891Z");
console.log(date.getDay());  // 2

The above code returns integer between 0-6 but we are interested in textual representation of day name e.g. Monday or Mon.

The traditional way 🧓

We know getDay() returns integer between 0-6 where 0 means Sunday. Hence we can define an array of week day names and make use of index returned by getDay().

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const DAY_NAME_OF_WEEK_SHORT = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
const DAY_NAME_OF_WEEK_LONG = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];

let date = new Date("2021-07-06T11:24:49.891Z");

console.log(DAY_NAME_OF_WEEK_LONG[date.getDay()]);    // Tuesday
console.log(DAY_NAME_OF_WEEK_SHORT[date.getDay()]);   // Tue

The above code works undoubtedly, however the new Intl API provides a better solution.

The modern way 😎

Intl.DateTimeFormat provides a robust way to format date and times in different locales. The constructor accepts two optional params Intl.DateTimeFormat(locale, options). The second param options accepts a variety of fields out of which we are interested in weekday. You can pass one out of three (long, short, narrow) values to weekday.

• { weekday: "long" } Full textual representation of week day e.g. Sunday Monday etc.
• { weekday: "short" } Short textual representation of week day e.g. Sun Mon etc.
• { weekday: "narrow" } Initials of week day e.g. S M etc. Note: Use it with caution it may result in same result for week days with same initials e.g. Sunday and Saturday for both it represents S.

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let date = new Date("2021-07-06T11:24:49.891Z");

// Tuesday
console.log(new Intl.DateTimeFormat("en-us", { weekday: "long" }).format(date));

// Tue
console.log(new Intl.DateTimeFormat("en-us", { weekday: "short" }).format(date));

// T
console.log(new Intl.DateTimeFormat("en-us", { weekday: "narrow" }).format(date));

Weekday in different locale 🌐

The Intl.DateTimeFormat simplifies the job a lot. You can use the API to get week day name in different locales (hindi, tamil etc.) too. Pass the desired locale in which you want week day name to the Intl.DateTimeFormat() constructor.

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let date = new Date("2021-07-06T11:24:49.891Z");

// मंगलवार
console.log(new Intl.DateTimeFormat("hi-in", { weekday: "long" }).format(date));

// मंगल
console.log(new Intl.DateTimeFormat("hi-in", { weekday: "short" }).format(date));

// మంగళవారం
console.log(new Intl.DateTimeFormat("te-in", { weekday: "long" }).format(date));

// మంగళ
console.log(new Intl.DateTimeFormat("te-in", { weekday: "short" }).format(date));

References

• MDN Web Docs DateTimeFormat
• ECMAScript
• Check browser compatibility

 
 
Happy Coding 👨‍💻