JavaScript - subtract seconds from date

In this article, we would like to show you how to subtract seconds from date in JavaScript.

Quick solution:

// ONLINE-RUNNER:browser;

const date = new Date('2021-06-30T00:00:00.000Z');

date.setSeconds(date.getSeconds() - 2); // subtracted 2 seconds from existing date

console.log(date.toISOString());        // 2021-06-29T23:59:58.000Z

1. Example reusable lambda function

In this example, we create a simple function that takes two arguments:

• date from which we want to subtract some seconds,
• seconds - a number of seconds we want to subtract.

Runnable example:

// ONLINE-RUNNER:browser;

const subtractSeconds = (date, seconds) => {
  let result = new Date(date);
  result.setSeconds(result.getSeconds() - seconds);
  return result;
};

let date = new Date('2021-06-30T00:00:00.000Z');

console.log(subtractSeconds(date, 1).toISOString());

Output:

2021-06-29T23:59:59.000Z

Note:

As you can see, the function also handles the case of the day change.

2. Extending existing Date class with Date.prototype

In this example, we add a function to the Date.prototype so we can use it on any date object.

// ONLINE-RUNNER:browser;

Date.prototype.subtractSeconds = function(seconds) {
    let date = new Date(this.valueOf());
    date.setSeconds(date.getSeconds() - seconds);
    return date;
}

let date = new Date('2021-06-30T00:00:00.000Z');

console.log(date.subtractSeconds(2).toISOString());

Output: 

2021-06-29T23:59:58.000Z