Implementation of linked list in Node JS

LinkedList.js

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

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

  size() {
    let counter = 0;
    let node = this.head;

    while (node) {
      counter++;
      node = node.next;
    }

    return counter;
  }

  removeFirst() {
    this.head = this.head.next;
  }

  getFirst() {
    return this.getAt(0);
  }

  getLast() {
    return this.getAt(this.size() - 1);
  }

  clear() {
    this.head = null;
  }

  removeLast() {
    this.removeAt(this.size() - 1);
  }

  insertLast(data) {
    let currLast = this.getLast();
    if (currLast) {
      currLast.next = new Node(data);
    } else {
      this.insertFirst(data);
    }
  }

  insertFirst(data) {
    this.head = new Node(data, this.head);
  }

  getAt(index) {
    let node = this.head;
    while (index && node) {
      node = node.next;
      index--;
    }

    return node;
  }

  removeAt(index) {
    if (!this.head) return;
    if (index === 0) {
      this.head = this.head.next;
      return;
    }

    let prevNode = this.getAt(index - 1);
    let currNode = this.getAt(index);
    if (prevNode) {
      prevNode.next = currNode && currNode.next;
    }
  }

  insertAt(data, index) {
    if (!this.head || index === 0) {
      this.insertFirst(data);
    }

    let prevNode = this.getAt(index - 1);
    let currNode = this.getAt(index);
    if (!currNode) {
      this.insertLast(data);
    }

    if (prevNode) {
      prevNode.next = new Node(data, currNode);
    }
  }

  forEach(fn) {
    let index = 0;

    while (index < this.size()) {
      let node = this.getAt(index);
      fn(node, index);
      index++;
    }
  }

  *[Symbol.iterator]() {
    let node = this.head;

    while (node) {
      yield node;
      node = node.next;
    }
  }
}

module.exports = { Node, LinkedList };