Ionic 4/5: exit from the app pressing back button - ionic-framework

Question

I need to exit from the app when the back button is pressed only in a certain page; in particular, let's say I have I have the app.component.ts and I have a page called HomePage. In app-routing.module.ts I have this routes:
const routes: Routes = [
{ path: '', redirectTo: 'home', pathMatch: 'full' },
{ path: 'home', loadChildren: './public/home/home.module#HomePageModule' }
];
So whever the user opens the app, it will see the HomePage as first page. If the user presses the back button, now it reloads the same page forever; I want to catch that pressing and exit the app. I've tried to use this in home.page.ts, but nothing happens:
backButtonSubscription: any;
this.backButtonSubscription = this.platform.backButton.subscribe(async () => {
console.log('lets exit!');
navigator['app'].exitApp();
});
Even the console.log is printed, as if the event is not caught. I've also tried with this:
this.platform.backButton.subscribeWithPriority(99999, () => {
navigator['app'].exitApp();
});
but the result is the same, so I'm wondering how it can be solved. I've found a lots of questions online, but there's no explanation that seems to solve this issue or to give a workaround.
Thanks for your help!

Answer 1

if you are using ionic 4 angular . try this
in AppComponent -> initializeApp
add
this.platform.backButton.subscribeWithPriority(0, () => {
navigator[‘app’].exitApp();
});
here is an example
initializeApp() {
this.platform.ready().then(() => {
this.statusBar.styleDefault();
this.splashScreen.hide();
this.platform.backButton.subscribeWithPriority(0, () => {
navigator['app'].exitApp();
});
});
}

Answer 2

in my case im using capacitor (ionic 5), try this if you're using capacitor too
import { Plugins } from '#capacitor/core';
const { App } = Plugins;
initializeApp() {
App.addListener('backButton', () => {
App.exitApp();
});
}

Answer 3

Ionic 5.
Another option its to use Platform, for me it woks well in case of using tabs:
p.s. better to use "init" service instead of app.component.ts to keep app init flow clean and obvious
constructor(
private platform: Platform,
private router: Router
) {
this.platform.backButton.subscribeWithPriority(-1, () => {
const url = this.router.url;
if (url === '/tabs/not-home') {
this.router.navigate(['/tabs/home']);
} else if (url === '/tabs/home') {
App.exitApp();
}
});
}