Author: John Au-Yeung

To simulate a click by using x, y coordinates in JavaScript, we can call the document.elementFromPoint with the x and y coordinates to get the element at those coordinates.

Then we call click on the returned element to click it.

For instance, if we have the following HTML:

<div>
  hello world
</div>

Then we can click it by writing:

document.addEventListener('click', (e) => {
  console.log(e.target)
})

const x = 10
const y = 10
document.elementFromPoint(x, y).click();

We set the x and y values to get the element at that point.

Then we call click on it to click it.

Then in the click listener that we added with addEventListener , we should see the element that’s clicked.

We can also dispatch the click event by using the MouseEvent constructor.

For instance, we can write:

document.addEventListener('click', (e) => {
  console.log(e.target)
})

const x = 10
const y = 10

const click = (x, y) => {
  const ev = new MouseEvent('click', {
    'view': window,
    'bubbles': true,
    'cancelable': true,
    'screenX': x,
    'screenY': y
  });
  const el = document.elementFromPoint(x, y);
  el.dispatchEvent(ev);
}
click(x, y)

We create the click function that clicks the element with coordinates x and y by using the MouseEvent constructor.

We pass in an object that sets the screenX and screenY to set the location of the click.

And then we get the element at the given x and y coordinates with document.elementFromPoint .

Finally, we call dispatchEvent on it with x and y to do the clicking.

To add 1 day to the current date with JavaScript, we can use the setDate method.

For instance, we can write:

const date = new Date();
date.setDate(date.getDate() + 1);
console.log(date)

to get the current day with getDate , then add 1 to it.

And then we pass that as the argument of setDate to add 1 to the current date .

We can also add 1 day to the current by adding 1 day in milliseconds.

For instance, we can write:

const date = new Date(Date.now() + (3600 * 1000 * 24))
console.log(date)

to get the current date and time in milliseconds with Date.now .

Then we add 3600 * 1000 * 24 milliseconds, which is the same as 1 day to it.

And we pass that to the Date constructor to get the date 1 day after the current date.

To exponentiate numbers with JavaScript, we can use the ** operator or the Math.pow method.

For instance, we can write:

const num = 2 ** 3

or:

const num2 = Math.pow(2, 3)

The first operand if ** is the base and the 2nd is the exponent.

The first argument of Math.pow is the base and the 2nd is the exponent.

As a result, we get 8 for num and num2 .

To get the date that is 30 days prior to the current date with JavaScript, we can call the setDate method with the current date subtracted by 30 to get the date 30 days before the current date.

For instance, we can write:

const today = new Date()  
const priorDate = new Date().setDate(today.getDate() - 30)  
console.log(priorDate)

We create today’s date with the Date constructor with no arguments.

Then we call setDate with getDate to get the current date and minus that by 30 to get the date 30 days before today .

Get the Date That is 30 Days Prior to the Current Date with Moment.js

We can also use the subtract or add methods that come with moment.js to get the date that’s 30 days before today.

For example, we can write:

const priorDate = moment().subtract(30, 'days');  
console.log(priorDate)  
const priorDate2 = moment().add(-30, 'days');  
console.log(priorDate2)

to compute the date that’s 30 days before today with the subtract or add methods.

The first argument is the number of days to add or subtract.

The 2nd argument is the unit.