Currently I have set up the cookie prompt to override document.cookie set method, so that it stores non-required cookies and waits for user input (which cookies the user allows to use in the web page) to decide about other cookies.

Code looks something like this:

const originalSetter = document.__lookupSetter__('cookie');

function newSetter(cookie) {
    if (isRequired(cookie)) {
        originalSetter(cookie);
    } 
    else {
        //store the cookie and decide later.
    }
}
document.__defineSetter__('cookie', newSetter);

Since the google analytics cookie is not a required one (at least in my page), is this the correct approach or is there another way to do this?