How to Add Hours to Date Object in JavaScript

Surprisingly, the JavaScript Date API does not provide a way to add hours to a Date object.

But we can create our own function to do this.

We don’t want to mutate the original Date object, so we can first create a new Date object and then manually set the hours.

function addHours(date, hours) {
  const newDate = new Date(date);
  newDate.setHours(newDate.getHours() + hours);
  return newDate;
}

We can use this utility function like so:

const date = new Date();           // Fri Feb 26 2021 20:08:30
const newDate = addHours(date, 1); // Fri Feb 26 2021 21:08:30