How to delete a node in the middle of a singly linked list

function deleteMiddleNode(node) {
  if (!node || !node.next) return;
  const data = node.next.data;
  const newNext = node.next.next;
  
  node.data = data;
  node.next = newNext;
}
function Node(data) {
  this.next = null;
  this.data = data;
}
Node.prototype.addToTail = function(data) {
  const end = new Node(data);
  let current = this;
  while (current.next !== null) {
    current = current.next;
  }
  current.next = end;
  return end;
};