Convert a Date object or string to timestamp in JavaScript

To convert a Date object or string to timestamp in JavaScript, you need to use the getTime() method of the Date object.

The get getTime() method returns a Unix timestamp in milliseconds. You can divide the result by 1000 to get the epoch in seconds:

const myDate = new Date("July 20, 2009");

const timeMillis = myDate.getTime() / 1000;

console.log(timeMillis); // 1248022800

If you have a date string, then use the Date() constructor to create a Date object from that string first before calling the getTime() method.

But note that you need to pass the date in a specific format to make the Date() constructor work.

If you have a date in dd/mm/yyyy format for example, the Date() constructor would return a NaN:

const myDate = new Date("25/01/2009").getTime();

console.log(myDate); // NaN

The Date() constructor works most reliably on a string with yyyy-mm-dd format, which is an ISO standard.

You need to split your string to an array, then pass each element into the Date() constructor as follows:

let dateStr = "25/01/2009";

let dateArr = dateStr.split("/");

const myDate = new Date(`${dateArr[2]}-${dateArr[1]}-${dateArr[0]}`);

console.log(myDate.getTime() / 1000); // 1232841600

Whenever you need to use the Date() constructor, always make sure that you’re passing a string in yyyy-mm-dd format to avoid any issues.

If you use the forward slash / as the date separator, change it to a dash - also.

And that’s how you convert a date object or string into a timestamp in JavaScript. Until next time! 🙌

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