JavaScript - get first day of month

In this article, we would like to show you how to get first day of month in JavaScript.

Quick solution:

// ONLINE-RUNNER:browser;

let date = new Date('Mon Aug 02 2021');
let firstDay = new Date(date.getFullYear(), date.getMonth(), 1);

console.log(firstDay); // Sun Aug 01 2021

Practical example

In this example, we use:

• date.getFullYear() - to get the year of the specified date,
• date.getMonth() - to get the month of the specified date,
• 1 in the Date() constructor stands for the day of the month.

// ONLINE-RUNNER:browser;

let date = new Date('Mon Aug 02 2021');
let firstDay = new Date(date.getFullYear(), date.getMonth(), 1);

console.log(firstDay); // Sun Aug 01 2021

Output:

Sun Aug 01 2021 00:00:00 GMT+0200 (Central European Summer Time)

References

• Date() constructor syntax - JavaScript