Generic pattern to check if Geolocation is available

Ionic Framework ionic-v3
1

I am new to Ionic and trying to come up with a good way to check if Geolocation is available before loading my app data.

I am trying to go with the following but the setTimeout does not appear to run after ten seconds.

import { Component } from '@angular/core';
import { Diagnostic, Geolocation } from 'ionic-native';
import { NavController } from 'ionic-angular';

@Component({
  selector: 'page-home',
  templateUrl: 'home.html'
})

export class HomePage {
  
  lat: number;
  lng: number;
  
  constructor(public navCtrl: NavController) {
    
  }
  
  gpsReady() : boolean {
    if( Diagnostic.isLocationAvailable() && Diagnostic.isLocationEnabled() && Diagnostic.isLocationAuthorized() ) {
        return true;
    } else {
        return false;
    }
  }
  
  locationReady() : boolean {
    if(this.lat && this.lng) {
        return true;
    } else {
        return false;
    }  
  }
  
  initiate() {
    if(this.gpsReady()) {
        Geolocation.getCurrentPosition().then((res) => {
          this.lat = res.coords.latitude;
          this.lng = res.coords.longitude;
          
          this.doStuff();
          
        }).catch((error) => {
            this.showToast('Could not get GPS position data. Try enabling GPS and restart the app.');
        });
    } else {
        // ask user to turn on GPS
    }
  }
  
  ngOnInit() {
    this.initiate();
  }
  
  doStuff() {
    if( this.locationReady() ) {
        // awesome app stuff
    } else {
        // wait 10 secs to se if GPS has fix
        setTimeout(function(){ this.initiate(); }, 10000);
    }
  }
      
}

Is there a “standard Ionic way” of ensuring Geolocation before continuing to load app data?