How to implement a singly linked list in JavaScript

function LinkedList() {
  this.head = null;
  this.tail = null;
}
function Node(value) {
  this.value = value;
  this.next = null;
}
LinkedList.prototype.contains = function(value) {
   if (!this.head || !this.tail) return false;
   
   let node = this.head;
   while (node) {
     if (node.value === value) return true;
     node = node.next;
   }
   return false;
};
 
LinkedList.prototype.indexOf = function() {
 
};
 
LinkedList.prototype.addToHead = function(value) {
  const node = new Node(value);
  
  if (!this.head && !this.tail) {
    this.head = this.tail = node;
  } else {
    node.next = this.head;
    this.head = node;
  }
};
 
LinkedList.prototype.addToTail = function (value){
  const node = new Node(value);
  
  if (!this.head && !this.tail) {
    this.head = this.tail = node;
  } else {
    this.tail.next = node;
    this.tail = node;
  }
};
 
LinkedList.prototype.insertAfter = function(target, value) {
  if (!this.head || !this.tail) return false;
  
  let node = this.head;
  const newNode = new Node(value);
  while (node) {
    if (node === target) {
      newNode.next = node.next;
      node.next = newNode;
    }
    node = node.next;
  }
};
 
LinkedList.prototype.getValues = function(){
  const values = [];
  
  let node = this.head;
  while (node) {
    values.push(node.value)
    node = node.next;
  }
  
  return values;
};
 
LinkedList.prototype.iterativeReverse = function(){
  let current = this.head;
  let prev = null;
  let next = null;
  
  // Swap head and tail
  this.head = this.tail;
  this.tail = current;
  
  // change pointers iteratively
  while (current) {
      next = current.next;
      
      current.next = prev;
      prev = current;
      current = next;
  }
  
  return this.tail;
  
};
 
LinkedList.prototype.recursiveReverse = function(){
  const current = arguments[0] !== undefined ? arguments[0] : this.head;
  const prev = arguments[1] !== undefined ? arguments[1] : null;
  
  if (!current) {
    let temp = this.head;
    this.head = this.tail;
    this.tail = temp;
    return this.head;
  }
  
  const next = current.next;
  current.next = prev;
  this.recursiveReverse(next, current)
 
};