Classes- Build a Library

Hello,
I am doing the React course and in the initial part on Javascript Classes I have a “Nan” when I log this : console.log(historyOfEverything.getAverageRating());
.
Here a link of the project:
https://www.codecademy.com/paths/build-web-apps-with-react/tracks/bwa-javascript-iterators-objects-and-classes/modules/learn-javascript-classes/projects/build-a-library

This is my code:


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(value) {
    this._isCheckedOut = value;
  }
  toggleCheckedOutStatus() {
     this._isCheckedOut = !this._isCheckedOut;
      } 

  getAverageRating() {
    let ratingsSum = 
    this.ratings.reduce((accumulator, rating) => accumulator + rating);
    return ratingsSum / this.ratings.lenght;  
  }

  addRating(value) {
    this.ratings.push(value);
  }
}

class Book extends Media{
  constructor(author, title, pages) {
    super(title);
    this._author = author;
    this._pages = pages;
  }
  get author() {
    return this._author;
  }
  get pages() {
    return this._pages;
  }
}
class Movie extends Media{
  constructor(director, title, runTime) {
    super(title);
    this._director = director;
    this._runTime = runTime;
  }
  get director() {
    return this._director = director;
  }
  get runTime() {
    return this._runTime = runTime;
  }
}
const historyOfEverything = new Book('Bill Bryson', 'A Short History of Nearly Everything', 544);
historyOfEverything.toggleCheckedOutStatus();
console.log(historyOfEverything.isCheckedOut);
historyOfEverything.addRating(4);
historyOfEverything.addRating(5);
historyOfEverything.addRating(5);
console.log(historyOfEverything.getAverageRating());

Thank you in advance for your help.

Everything should be fine once you checked the spelling of ‘length’.

2 Likes

Thank you so much mirja_t !

1 Like