Is there an opposite of remove function on JS?

Question

I know that on JS exists a remove() function:

HTMLElement.remove();

I'm just interested to know, if there is a function that does the opposite of remove().

Answer 1

Recently I learned add() function in one of the online tutorials. This worked totally OK on my codes.
Example:

 const closeModal = function() {
    modal.classList.add('hidden');
}

const openModal = function() {
    modal.classList.remove('hidden');
}