Cannot assign component variable value inside geocode function

Question

GetLocation(address: string) {
  var geocoder = new google.maps.Geocoder();
  geocoder.geocode({ 'address': address }, (results, status) => {
    if (status == google.maps.GeocoderStatus.OK) {
      this.lat = results[0].geometry.location.lat(); 
      this.lng = results[0].geometry.location.lng();   <== this.lat value is undefined
    }
    else {
      alert("Something went wrong : " + status);
    }
  });
}

Here I cannot assign value of component level variable 'lat' and 'lng' inside the geocode function. FYI: there are values in location object of result inside it, but after assigning the value it is still undefined I don't know why?

Answer 1

import { Component, OnInit, NgZone } from '@angular/core';  <= 1. I have to import NgZone

constructor(private ngZone: NgZone) { }  <= 2. declared it here

ngOnInit() { }

GetLocation(address: string) {
  var geocoder = new google.maps.Geocoder();
  geocoder.geocode({ 'address': address }, (results, status) => this.ngZone.run(() => { <= 3. and used it here
    if (status == google.maps.GeocoderStatus.OK) {
      this.lat = results[0].geometry.location.lat();
      this.lng = results[0].geometry.location.lng();
    }
    else {
      alert("Something went wrong : " + status);
    }
  }));
}

I found the solution for this. I have to import NgZone from '@angular/core' and used this.ngZone.run() function inside call back function as in 3. hint.