Zoom to specified markers react-native-maps
In the MapView component docs, there are a few methods: fitToElements, fitToSuppliedMarkers and fitToCoordinates. https://github.com/airbnb/react-native-maps/blob/master/docs/mapview.md#methods
If you want to zoom the map in on some collection of markers on load, you can use componentDidMount to zoom in after the initial render:
class SomeView extends Component { constructor() { this.mapRef = null; } componentDidMount() { this.mapRef.fitToSuppliedMarkers( someArrayOfMarkers, false, // not animated ); } render() { <MapView ref={(ref) => { this.mapRef = ref }} > { someArrayOfMarkers } </MapView> }}