How to zoom position in native google maps?

Ionic Framework ionic-v3
1 
	ionViewDidLoad() {
		GoogleMap.isAvailable().then( () => {
			this.loadMap()
		}).catch(() => {
			alert('Maps not working')
		})
	}

	loadMap() {
		let map:GoogleMap  = new GoogleMap('map', {
			backgroundColor: 'white',
			timeout: 10000, 
			enableHighAccuracy: true,
			controls: {
				compass: true,
				myLocationButton: true,
				indoorPicker: true,
				zoom: true
			},
			gestures: {
				scroll: true,
				tilt: true,
				rotate: true,
				zoom: true
			}
		})

		let default_location: GoogleMapsLatLng = new GoogleMapsLatLng(AppConfig.DEFAULT_MAP_LOCATION.lat, AppConfig.DEFAULT_MAP_LOCATION.long)

		map.one(GoogleMapsEvent.MAP_READY).then(() => {
			this.loader.dismiss()

			console.log('Map is ready!')

			let position: CameraPosition = {
				target: default_location,
				zoom: 20
			}

			// // move the map's camera to position
			map.moveCamera(default_location);
		})
	}

The main problem is that i cant set zoom. It is always the same no matter what I did

2

let map:GoogleMap = new GoogleMap(‘map’, {
backgroundColor: ‘white’,
timeout: 10000,
enableHighAccuracy: true,
zoom: 20,
controls: {
compass: true,
myLocationButton: true,
indoorPicker: true,
zoom: true
},
gestures: {
scroll: true,
tilt: true,
rotate: true,
zoom: true
}
})