Just a small reminder. Javascript allows you to call methods based on their name. So if a DOM element has a addClass and removeClass which both take the same argument we could write:

var someClass = 'some-class';
var hasClass = element.hasClass(someClass);
if(hasClass){
    element.addClass(someClass);
} else {
    element.removeClass(someClass);
}

but we could also write

var someClass = 'some-class';
var hasClass = element.hasClass(someClass);
element[hasClass ? 'addClass' : 'removeClass'](someClass);

Sometimes this means you can use this technique to write powerful one liners.