ionic4/angular: overlay `getTop` can return `undefined`

[Pierrci]

Bug Report

Ionic version:

[x] 4.x

Current behavior: In the angular package, the return type of the getTop method in OverlayBaseController is Promise<Overlay>

Expected behavior: The return type should be Promise<Overlay | undefined>

Steps to reproduce: Use any component extending OverlayBaseController and call the getTop method without any alert currently present. With the AlertController for example, returned object will be of type Promise<HTMLIonAlertElement>, while it should be Promise<HTMLIonAlertElement | undefined>.

Related code:

import { Component, OnInit } from '@angular/core';
import { AlertController } from '@ionic/angular';

@Component({
  selector: 'app-home',
  templateUrl: 'home.page.html',
  styleUrls: ['home.page.scss'],
})
export class HomePage implements OnInit {
  constructor(private alertController: AlertController) {}

  async ngOnInit() {
    const undefinedAlert = await this.alertController.getTop(); // typed as HTMLIonAlertElement
    alert(`type of alert is ${typeof undefinedAlert}`); // typeof undefinedAlert === 'undefined'
    undefinedAlert.dismiss(); // still possible because of the typing, will throw an error
  }
}

Other information:

Ionic info:

Ionic:

   ionic (Ionic CLI)             : 4.10.3 (/usr/local/lib/node_modules/ionic)
   Ionic Framework               : @ionic/angular 4.1.1
   @angular-devkit/build-angular : 0.13.6
   @angular-devkit/schematics    : 7.2.4
   @angular/cli                  : 7.3.6
   @ionic/angular-toolkit        : 1.4.0

System:

   NodeJS : v11.6.0 (/usr/local/bin/node)
   npm    : 6.5.0
   OS     : macOS Mojave

[Pierrci]

Just submitted the related PR

[brandyscarney]

It seems the PR was merged so I'm going to close this, thanks for the issue!

[ionitron-bot[bot]]

Thanks for the issue! This issue is being locked to prevent comments that are not relevant to the original issue. If this is still an issue with the latest version of Ionic, please create a new issue and ensure the template is fully filled out.