用于从排序链接列表中删除重复项的 Javascript 程序

Given linked list is: 1-> 2 -> 2 -> 3 -> 4 -> 4 -> 4 -> 5 -> 5 -> 5-> 6-> null
Output: 1 -> 2 -> 3 -> 4 -> 5 -> 6 -> null

// class to provide structure to linked list node
class Node{
   constructor(val){
      this.value = val
      this.next = null
   }
}
// function to print the linked list
function print(head){
   var temp = head;
   if(head == null){
      console.log("The given linked list is empty");
   } else {
      var ans = ""
      while(temp.next != null){
         ans += temp.value;
         ans += " -> "
         temp = temp.next
      }
      ans += temp.value
      ans += " -> null"
   }
   console.log(ans)
}
// function to add data in linked list 
function add(data, head, tail){
   var new_node = new Node(data);
   if(head == null){
      head = new_node
      return new_node
   } else {
      tail.next = new_node;
      return new_node
   }
}
// function to remove the duplicate numbers 
function removeDupli(head){
   // if linked list is empty 
   if(head == null){
      return head;
   }
   // if linked list is of size one 
   if(head.next == null){
      return head;
   }
   var temp = head
   var next = head.next
   while(next != null){
      if(temp.value == next.value){
         next = next.next;
         temp.next = next;
      } else {
         next = next.next;
         temp = temp.next;
      }
   }
   return head;
}
// defining linked list
var head  = new Node(1)
var tail  = head
tail = add(2,head, tail)
tail = add(2,head, tail)
tail = add(3,head, tail)
tail = add(4,head, tail)
tail = add(4,head, tail)
tail = add(4,head, tail)
tail = add(5,head, tail)
tail = add(5,head, tail)
tail = add(5,head, tail)
tail = add(6,head, tail)
console.log("The given linked list is: ")
print(head)
// calling function to remove duplicate elements 
head = removeDupli(head)
console.log("The Linked list after removal of duplicate integers is: ")
print(head)