Creating the Files

In the components folder create three Custom Elements:

components/MenuPage.js

export default class MenuPage extends HTMLElement {
    constructor() {
        super();
    }
}
customElements.define("menu-page", DetailsPage);

components/DetailsPage.js

export default class DetailsPage extends HTMLElement {
    constructor() {
        super();
    }
}
customElements.define("details-page", DetailsPage);

components/OrderPage.js

export default class OrderPage extends HTMLElement {
    constructor() {
        super();
    }
}
customElements.define("order-page", DetailsPage);