Linked List Using Typescript

Linked list is a collection of nodes where every node has data and pointer to the next node. It is often compared to an array as it can be used to implement other data structures like queue or stack .

class ListNode {
  data:number;
  next:ListNode;
  
  constructor(data:number){
   this.data = data;
  }
  
  setNext(next:ListNode){
    this.next = next;
  }
  
  getNext(){
   return this.next;
  }

  getData() {
      return this.data;
  }
  
}

class LinkedList{
    head: ListNode = null;

    add(data: number) {
        if (this.head == null) {
            this.head = new ListNode(data);
        } else {
            var newNode = new ListNode(data);
            var current = this.head;
            while (current.getNext() != null) {
                current = current.getNext();
            }
            current.setNext(newNode);
        }
    }
    
    indexOf(data:number) {
      var found = false;
      var current = this.head;
      var index = 1;
      while (current != null && !found) {
        if (current.getData() == data){
          found = true;
          break;
        }else{
          current = current.getNext();
          index ++;
        }
      }
      return index;
    }
    
    elementAt(index:number){
     index = index-1;
     var current = this.head;
     var element = null;
     var cnt = 0;
     while (current != null){
       if (cnt == index){
        element=current.getData();
        break;
       } else{
        cnt++;
        current = current.getNext();
       }
     }
     return element;
    }
    
    remove(data:number){
      var current = this.head;
      if (current.getData() == data){
        this.head = this.head.getNext();
      } else{
        var prev = null;
        while(current != null && current.data != data){
          prev = current;
          current = current.getNext();
        }
        if (current  != null) {
         prev.setNext(current.getNext());
        }else{
         console.log("The data " + data +  "was not found");
        }
      }
    }
    
    size() {
      var current = this.head;
      var cnt = 0;
      while(current != null){
       cnt++;
       current = current.getNext();
      }
      return cnt;
    }

    print(){
      var current = this.head;
      var result = "";
      while(current != null){
        result += current.getData();
        if (current.getNext() != null)
        result += "-->";
        current = current.getNext();
      }
      console.log(result);
    }
}