visibilitychange gets called multiple times if using fullscreen api

Question

I am using visibilitychange event of browser. All looks good.

After clicking on one of my buttons, I use fullScreen API to take website into fullscreen mode.

The issue that I have is visibilitychange event gets called twice when getting into fullscreen mode and when I exit fullscreen mode, visibilitychange gets called 4 times . Is there any reason why this is happening? Isn't there any way that it will only get called once ?

this.visibility = () => {
          console.log("this gets called multiple times ");
}
document.addEventListener('visibilitychange', this.visibility, false);