I'm facing google map issue

There is no error occured but google map is not showing.
actually i want to find near by location.

at first i put the google API key into the index.htm
like that
<script src="http://maps.google.com/maps/api/js?key=AIzaSyAEEC0OzbKyyPEHc-vHUp_bXRVcNEyyl5w&libraries=places"></script>


 initMap() {
       let pyrmont = {lat: 22.9868, lng: 87.8550};

        this.map = new google.maps.Map(document.getElementById('map'), {
          center: pyrmont,
          zoom: 15

        this.infowindow = new google.maps.InfoWindow();
        let service = new google.maps.places.PlacesService(this.map);
          location: pyrmont,
          radius: 500,
          type: ['store']
        }, this.callback);

        callback(results, status) {
        if (status === google.maps.places.PlacesServiceStatus.OK) {
          for (var i = 0; i < results.length; i++) {

     createMarker(place) {
        var placeLoc = place.geometry.location;
        var marker = new google.maps.Marker({
          map: this.map,
          position: place.geometry.location

        google.maps.event.addListener(marker, 'click', function() {
          this.infowindow.open(this.map, this);

what i’m wrong? if i’m wrong please tell me how can i fix it.
Thanks in advance.

i’m fix the map issue.i’m just forgot to call the function into the ionViewDidLoad();
like that


but there is one another problem occur.marker is not showing.