ionic 3 javascript google map marker onclick error

Question

I am using Ionic 3 with Javascript Google map API. Here is my code:

google.maps.event.addListener(marker, 'click', (function(marker, i) {
       return function() {

        this.callOrder();

        //infowindow.setContent(locations[i]['location']);
        //infowindow.open(map, marker);
      }
    })(marker, i));

this.callOrder(); this is my custom function.

I want to click each and every marker and when I click, this.callOrder(); function will call. But now I am getting an error like:

"TypeError: this.callOrder is not a function. (In 'this.callOrder()', 'this.callOrder' is undefined)"

Anyone can give me an idea or a solution?