Call a classes function from within window scope

I have a simple class,

class TestClass {
   init() {
       this.loadGoogle();
   }
   
   initializeSearch() {
       alert("here");
   }
   
   loadGoogle() {
       const script = document.createElement('script');
        script.src = 'https://maps.googleapis.com/maps/api/js?key={MY_KEY}&libraries=places&callback=initMap';
        script.async = true;

        window.initMap = () => {
        //JS API IS LOADED
            this.initializeSearch();
        };

        document.head.append(script);
   }
}

I am having trouoble calling the intializeSearch method when the callback is fired. I am assuming it’s because this is out of scope? Can I bring this into the scope of the window global?