window.modules.register("$app", () => {
    const App = window.modules.require("App");

    if (!window._APP_ENV)
        throw new Error("$app: could not find window._APP_ENV");
    if (!App)
        throw new Error("$app: require('App') returned undefined");

    const initialLoading = document.getElementById("initial-loading");
    if (initialLoading) {
        initialLoading.parentElement.removeChild(initialLoading);
    }
    
    const appMountElement = document.createElement("div");
    document.body.appendChild(appMountElement);

    const app = new App(appMountElement);
    app.mount();

    return app;
});