jQuery - Check if DOM element already exists

Question

I am trying to add some form elements dynamically via Ajax with jQuery. I want to make sure that I don\'t create the same element twice, so I only want to add it if it hasn\

Answer 1

(()=> {
    var elem = document.querySelector('.elem');  
    (
        (elem) ? 
        console.log(elem+' was found.') :
        console.log('not found')
    )
})();

If it exists, it spits out the specified element as a DOM object. With JQuery $('.elem') it only tells you that it's an object if found but not which.