Hello, my main JS has come up with this error message and I have looked through my code and I am still not sure how to solve my issue. would it be possible for someone to assist me on this matter.
i have posted my error message and code below for you to go through. 
/home/ccuser/workspace/learn-javascript-classes-build-a-library/app.js:35
this.rating.push(value);
^
TypeError: Cannot read property ‘push’ of undefined
at Book.addRating (/home/ccuser/workspace/learn-javascript-classes-build-a-library/app.js:35:16)
at Object. (/home/ccuser/workspace/learn-javascript-classes-build-a-library/app.js:73:21)
at Module._compile (module.js:571:32)
at Object.Module._extensions…js (module.js:580:10)
at Module.load (module.js:488:32)
at tryModuleLoad (module.js:447:12)
at Function.Module._load (module.js:439:3)
at Module.runMain (module.js:605:10)
at run (bootstrap_node.js:427:7)
at startup (bootstrap_node.js:151:9)
class media {
constructor (title) {
this._title = title;
this._isCheckedOut = false;
this._rating = [];
}
get title() {
this._title;
}
get isCheckedOut() {
this._isCheckedOut;
}
get rating() {
this._rating;
}
set isCheckedOut(value) {
this._isCheckedOut = value;
}
toggleCheckedOutStatus() {
this.isCheckedOut = !this.isCheckedOut;
}
getAverageRating() {
let ratingSum =
this.rating.reduce((accumulator, rating) => accumulator + rating);
return ratingSum / this.rating.length
}
addRating(value) {
this.rating.push(value);
}
}
class Book extends media {
constructor(author, title, pages) {
super(title)
this.author
this.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;
}
get runTime() {
return this._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())