Linked List in JavaScript

class Node {  constructor(data, next = null) {    this.data = data;    this.next = next;  }}class LinkedList {  constructor() {    this.head = null;  }  // Inserts a Node into the Linked List  insertFirst(data) {    this.head = new Node(data, this.head);  }  // Returns the number of nodes  size() {    let node = this.head;    let count = 0;    while (node) {      count++;      node = node.next;    }    return count;  }  // Returns the first Node  getFirst() {    return this.head;  }  // Returns the last Node  getLast() {    if (!this.head.next) {      return null;    }    let node = this.head;    while (node) {      if (!node.next) {        return node;      }      node = node.next;    }  }  // Removes all Nodes from the Linked List  clear() {    this.head = null;  }  // Removes the first Node from the Linked List  removeFirst() {    if (this.head) {      this.head = this.head.next;    }  }}

let list = new LinkedList();list.insertFirst(1);list.insertFirst(2);list.insertFirst(3);// list = {//   head: {//     data: 3,//     next: {//       data: 2,//       next: {//         data: 1,//         next: null//       }//     }//   }// }list.getFirst() // { data: 3, next:... }list.getLast() // { data: 1, next: null }list.size() // 3list.removeFirst() // { head: { data: 2, next:... }}list.clear() // { head: null }