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:

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let date = new Date('Mon Aug 02 2021');

let firstDay = new Date(date.getFullYear(), date.getMonth(), 1);

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

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.

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let date = new Date('Mon Aug 02 2021');

let firstDay = new Date(date.getFullYear(), date.getMonth(), 1);

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

Output:

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

• Date() constructor syntax - JavaScript