class Node {
  constructor(value, next = null) {
    this.value = value;
    this.next = next;
  }
}


class SLL {
  constructor() {
    this.head = null;
    this.tail = null;
    this.length = 0;
  }

  add(value) {
    const node = new Node(value);
    let currentNode = this.head;

    if (!currentNode) {
      this.head = node;
      this.tail = node;
      this.length++;

      return node;
    } else {
      while (currentNode.next) {
        currentNode = currentNode.next
      }
      currentNode.next = node;
      this.tail = node;
      this.length++;
      return node;
    }
  }

  traverse() {
    let currentNode = this.head;
    for (let i = 0; i < this.length; i++) {
      console.log(currentNode.value);
      currentNode = currentNode.next;
    }
  }
  remove(location) {
    if (location === 0) { // we want to delete first element
      this.head = this.head.next;
      this.length--;
      if (this.length === 0) { // if there are no more nodes in this list
        this.tail = null;
      }
    } else { //if any inside node is to be deleted
      let currentNode = this.head;
      for (let i = 0; i < location - 1; i++) {
        currentNode = currentNode.next; // we need to traverse till we find the location
      }
      currentNode.next = currentNode.next.next; // delete the required node
      this.tail = currentNode;
      this.length--;
    } //end of else

  }
}

const node = new SLL();

node.add(5);
node.add(9);
node.add(15);
node.traverse();
// console.log(JSON.stringify(node, 0, 2))
// node.remove(2);
// console.log(JSON.stringify(node, 0, 2))
// node.remove(1);
// console.log(JSON.stringify(node, 0, 2))