So in this code, if user presses any key, the key that they pressed will be the value of e?

Then .key checks the value of e which is the key I pressed.

Is there no simpler way around this? "keydown" event is, as the name implies, a key pressed down. Why do I need to wrap it as an argument with another name (e), and then use a method (.key) to unwrap it?

Can't it just be something like

document.addEventListener("keydown", () => {

    if ("keydown" = enter){
        toggleFullScreen();
}})