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JavaScript - subtract days from date

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Created by:

troya

692

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

Quick solution:

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const date = new Date('2021-06-30');
date.setDate(date.getDate() - 2);  // subtracted 2 days from existing date
​
console.log(date.toISOString());   // 2021-06-28T00:00:00.000Z

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or:

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const date = new Date('2021-06-30');
const newDate = new Date(date.getTime() - 2 * (24 * 60 * 60 * 1000));  // subtracted 2 days from existing date
​
console.log(newDate.toISOString());  // 2021-06-28T00:00:00.000Z

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1. Example reusable lambda function

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

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

Runnable example:

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const subtractDays = (date, days) => {
  let result = new Date(date);
  result.setDate(result.getDate() - days);
  return result;
};
​
let date = new Date('2021-06-30');
let result = subtractDays(date, 3);
​
console.log(result.toISOString());  // 2021-06-27T00:00:00.000Z

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2. Extending existing `Date` class with `Date.prototype`

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

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Date.prototype.subtractDays = function (days) {
  let date = new Date(this.valueOf());
  date.setDate(date.getDate() - days);
  return date;
};
​
let date = new Date('2021-06-30');
let result = date.subtractDays(2)
​
console.log(result.toISOString());  // 2021-06-28T00:00:00.000Z