I have problem in the 'removeElement(element)' in the doubly linked list

Question

I am facing a problem in the remove element in the list. When I want to remove the element in the list it not able to remove but other function works properly such as adding and removing at index.

 class Node{
constructor(element){
    this.element = element;
    this.right = null;
    this.left = null;
}
}

class DLinkList{
constructor(){
    this.head = null;
    this.tail = null;
    this.size = 0;
}

addFront(element){
    var node = new Node(element);

    var curr;

    if(this.head === null){
        this.head = node;
        this.tail = node;
    }else{
        this.head.left = node;
        node.right = this.head;
        this.head = node;
    }
    this.size++;
}

addAtIndex(element,index){
    var node = new Node(element);

    var curr,prev;

    if(this.head === null){
        this.head = node;
        this.tail = node;
    }else{
        var it = 0;

        curr = this.head;
        while(it < index){
            it++;
            prev = curr;
            curr = curr.right;
        }
        node.right = curr;
        prev.right = node;
        node.left = prev;
    }
    this.size++;
}

removeAtIdex(index){
    var curr,prev, it = 0;
    if(index > 0 && index > this.size){
        return false;
    }else{
        curr = this.head;
        while(it < index){
            it++;
            prev = curr;
            curr = curr.right;
        }
        prev.right = curr.right;
        curr.right.left = prev;
    }
    this.size--;
}

removeElement(element){
    var curr,prev = null;

    curr = this.head;
    while(curr != null){
        if(curr.element === element){
            if(prev === null){
                this.head = curr.right;
            }else{
                prev.right = curr.right;
            }
            this.size--;
        }
        prev = curr;
        curr = curr.next;
    }
    return -1;
}

printList(){
    var curr = this.head;
    var str = ''
    while(curr){
        str += curr.element + ' ';
        curr = curr.right;
    }
    console.log(str);

}
}

var ll = new DLinkList();
ll.addFront(2);
ll.addFront(3);
ll.addFront(4);
ll.addAtIndex(5,2);
ll.printList(); 
ll.removeAtIdex(1);
ll.printList();
ll.removeElement(5);
ll.printList();
console.log(ll);

output:

4 3 5 2

4 5 2

4 5 2


DLinkList {
  head: Node {
   element: 4,
   right: Node { element: 5, right: [Node], left: [Circular] },
   left: null
  },
  tail: Node {
   element: 2,
   right: null,
   left: Node { element: 3, right: [Node], left: [Node] }
  },
  size: 3
}

Answer 1

You use a non-existing property name: next. There is no curr.next. It should be curr.right.

Also, don't forget to update left and tail:

    if (curr.right === null) {
        this.tail = prev;
    } else {
        curr.right.left = prev;
    }