Using Classes in JavaScript

as a beginner I tried to use classes in JavaScript because I started to learn programming with C#.

So i want to store a note (with a title and a text) to a data store. These are my small classes:

class Note{ // The single note
  constructor(noteTitle, noteText) { // set the notes title and text
    title = noteTitle;
    text = noteText;
  }

  var title;
  var text;
}

class Notestore{
  var notes = []; // stores all the notes

  function AddNote(note){
    notes.push(note); // add a new note to the list
  }
}

class NoteController{
  var store = new NoteStore(); // get the reference to the store

  function CreateNote(title, text){ // create a new note and store it
    store.AddNote(new Note(title, text));
  }
}

So when I start the application it says,

var store = new NoteStore();

is not defined. My NoteController is the first class getting called. What do I have to change, that my classes should work =?

Thanks for help!