Build a library project error #9000

Hello all!
This is my first question here, so I hope I will write everything clear.
I have been doing this project with walkthrough and I think I did everything exactly the same. Nevertheless, my code is not working. It constantly throws an error #9000
I have been trying to solve it for a couple of hours and it’s killing me, hense this question! :slight_smile:
let me post my code here + the complete link.

class Media {

  constructor(title) {

    this._title = title;

    this._isCheckedOut = false;

    this._ratings = [];


  get title() {

    return this._title;


  get isCheckedOut() {

    return this._isCheckedOut;


  get ratings() {

    return this._ratings;


  set isCheckedOut(newIsCheckedOut) {

    this._isCheckedOut = newIsCheckedOut;



  toggleCheckOutStatus() {

    this.isCheckedOut = !this.isCheckedOut;


  getAverageRating() {

   let ratingSum = this.ratings.reduce((accumulator, rating) => accumulator + rating);

   return ratingSum / this.rating.length;


  addRating(value) {




class Book extends Media () {

  constructor(author, title, pages) {


    this._author = author;

    this._pages = pages;


  get author() {

    return this._author;


  get pages() {

    return this._pages;



and this is the error

class Movie extends Media() {

TypeError: Class constructor Media cannot be invoked without 'new'
    at Object.<anonymous>

thank you for assisting. Have a nice day.

Hi, could you paste a link to said project?

of course :slight_smile:

Leave off the parens. We don’t want to invoke a function in the signature line.

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