ionic 5 android hardware back button doesn't exit app

import { IonRouterOutlet, Platform } from '@ionic/angular';
import { Plugins } from '@capacitor/core';
const { App } = Plugins;

...

constructor(
  private platform: Platform,
  private routerOutlet: IonRouterOutlet
) {
  this.platform.backButton.subscribeWithPriority(-1, () => {
    if (!this.routerOutlet.canGoBack()) {
      App.exitApp();
    }
  });
}


This example shows the application exiting when the user presses the hardware back button and there is nothing left in the navigation stack. It is also possible to display a confirmation dialog before quitting the app.

It is recommended to check whether or not the user is on the root page prior to exiting the application. Developers can use the canGoBack method on IonRouterOutlet in Ionic Angular and IonRouter in Ionic React and Ionic Vue.