IonViewWillEnter not triggered from app reopened from background

I am trying to trigger a function when a user has minimized app in the background and then reopens it. How can I identify when the user has come back to app after being minimized in the background? I tried IonViewWillEnter but this seems to not trigger from background mode

That’s beyond Ionic’s scope basically. Javascript doesn’t know when an app is reopened.
You could use Cordova Resume though I think, not sure how you’d implement it though.