javascript – simple linked list traversal issue

I have implemented a single linked list using javascript. Please find the code below:

class Node {
  constructor(data) {
    this.data = data;
    this.nextElement = null;
  }
}

class LinkedList {
  constructor() {
    this.head = null;
  }

  isEmpty() {
    return this.head === null;
  }

  insertAtHead(data) {
    const tempNode = new Node(data);
    tempNode.nextElement = this.head;
    this.head = tempNode;
  }

  traverse() {
    let current = this.head;
    while (current.nextElement != null) {
      console.log("node data", current.data);
      current = current.nextElement;
    }
  }

  insertAtTail(data) {
    const tempNode = new Node(data);
    if (this.head === null) {
      this.head = tempNode;
      return;
    }

    let currentNode = this.head;
    while (currentNode.nextElement != null) {
      currentNode = currentNode.nextElement;
    }

    currentNode.nextElement = tempNode;
  }
}

const linkedList = new LinkedList();
linkedList.insertAtTail(12);
linkedList.insertAtTail(23);
linkedList.insertAtTail(25);

linkedList.traverse();

But the traverse method never prints the last element. What am I missing here? The insertAtTail method looks correct though. Could anyone please let me know.

thanks

Answer

In the traverse, you need to check all nodes not until the next one is null.

so I just removed the .nextElement from the traverse and it works fine

class Node {
  constructor(data) {
    this.data = data;
    this.nextElement = null;
  }
}

class LinkedList {
  constructor() {
    this.head = null;
  }

  isEmpty() {
    return this.head === null;
  }

  insertAtHead(data) {
    const tempNode = new Node(data);
    tempNode.nextElement = this.head;
    this.head = tempNode;
  }

  traverse() {
    let current = this.head;
    while (current) { // Here
      console.log("node data", current.data);
      current = current.nextElement;
    }
  }

  insertAtTail(data) {
    const tempNode = new Node(data);
    if (this.head === null) {
      this.head = tempNode;
      return;
    }

    let currentNode = this.head;
    while (currentNode.nextElement != null) {
      currentNode = currentNode.nextElement;
    }

    currentNode.nextElement = tempNode;
  }
}

const linkedList = new LinkedList();
linkedList.insertAtTail(12);
linkedList.insertAtTail(23);
linkedList.insertAtTail(25);


linkedList.traverse();