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() // 3
list.removeFirst() // { head: { data: 2, next:... }}
list.clear() // { head: null }