Пример методов и аксессов частного класса в ES12

// Let's create a class named User.
class User {
    constructor() {}

    // The private methods can be created by prepending '#' before
    // the method name.
    #generateAPIKey() {
        return "d8cf946093107898cb64963ab34be6b7e22662179a8ea48ca5603f8216748767";
    }

    getAPIKey() {
        // The private methods can be accessed by using '#' before
        // the method name.
        return this.#generateAPIKey();
    }
}

const user = new User();
const userAPIKey = user.getAPIKey();
console.log(userAPIKey); // This will print: d8cf946093107898cb64963ab34be6b7e22662179a8ea48ca5603f8216748767
Outrageous Ostrich