How to Clone a Date Object in JavaScript

In this tutorial, we will show how you can clone or copy a Date instance. The following example clones the current date which becomes possible with the getTime() method of the Date object which returns the number of milliseconds since 1 January 1970 00:00:00 (epoch time):

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<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
  </head>
  <body>
    <script>
      let currentDate;
      currentDate = new Date();
      document.write(currentDate);
      let clonedDate = new Date(currentDate.getTime());
      document.write("<br>" + clonedDate);
    </script>
  </body>
</html>

The valueOf() method for Date objects performs the same result as the getTime() method (the number of milliseconds since epoch time) and returns the primitive value of a Date object.

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
  </head>
  <body>
    <script>
      let date = new Date()
      document.write(date);
      let copyOf = new Date(date.valueOf())
      document.write("<br>" + copyOf);
    </script>
  </body>
</html>

The getTime() Method

The Date.prototype.getTime() method returns the number of milliseconds since the Unix Epoch. It uses UTC standard for the time representation. The method can be used to assign a date and time to another Date object. It is functionally equivalent to the valueOf() method.