JavaScript - subtract years from date

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

Quick solution:

// ONLINE-RUNNER:browser;

const date = new Date('2021-06-30');

date.setYear(date.getFullYear() - 2); // subtracted 2 years from existing date

console.log(date.toISOString());      // 2019-06-30T00:00:00.000Z

1. Example reusable lambda function

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

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

Runnable example:

// ONLINE-RUNNER:browser;

const subtractYears = (date, years) => {
  const result = new Date(date);
  result.setFullYear(result.getFullYear() - years);
  return result;
};


// Usage example:

const date = new Date('2021-06-30');
const newDate = subtractYears(date, 2); // subtracted 2 years from existing date

console.log(newDate.toISOString()); // 2019-06-30T00:00:00.000Z

Output:

2019-06-30T00:00:00.000Z

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.subtractYears = function (years) {
  this.setFullYear(this.getFullYear() - years);
};

// Usage example:

const date = new Date('2021-06-30');
date.subtractYears(2); // subtracted 2 years from existing date

console.log(date.toISOString()); // 2019-06-30T00:00:00.000Z

Output: 

2019-06-30T00:00:00.000Z