Keyboard-activated function

On a website of my clients there is a function in Javascript that pressing alt + 5 activates this function:

var chgpgPage = {
    goToPrincipal:function(){
        window.location.href = 'www.mysite.org';
    },
}      

The part of the code that triggers the function is this:

: this.AV102pressedSelected.Key == "alt+5"
? chgpgPage.goToPrincipal()

I now need the alt + 4 button to trigger another function that would be this:

require(["dojo", "dijit/form/Button"], function() {
    
    // Invert Button
    new dijit.form.Button({
        onClick: function() {
            dojo.toggleClass(document.documentElement, 'inverted');
        }
    }, 'invertButton');
    
});

How would the trigger code look?

: this.AV102pressedSelected.Key == "alt+4"
? ???????????????????

How would you go about triggering the above function? Since it doesn't have var like the other one?

Today the invertButton function is triggered by a button:

<button id="invertButton">Click to Invert</button>

Thank you for your help!

I think you can add a function in chgpgPage like this,

var chgpgPage = {
    goToPrincipal:function(){
        window.location.href = 'www.mysite.org';
    },
    invert:function(){
        require(["dojo", "dijit/form/Button"], function() {
            ojo.toggleClass(document.documentElement, 'inverted');
        });
    }
}

invert function will have the logic to invert. And you will trigger this function as:

: this.AV102pressedSelected.Key == "alt+4"
? chgpgPage.invert()