MapView.js

// MapView.js
var React = require('react-native');
var { View, Text, TouchableOpacity, requireNativeComponent } = React;
var RCTMapperManager = require('NativeModules').MapperManager;


class MapView extends React.Component {
  foobar(){
     RCTMapperManager.logstuff(
      React.findNodeHandle(this),
      "hello"
    );
  }
  render() {
    return (

      <View>
      <TouchableOpacity onPress={this.foobar.bind(this)} >

      <Text> Foobarmap </Text>
      </TouchableOpacity>


      <RCTMap ref="map" {...this.props} />
        </View>
    )
  }
}

MapView.propTypes = {
  /**
   * When this property is set to `true` and a valid camera is associated
   * with the map, the camera’s pitch angle is used to tilt the plane
   * of the map. When this property is set to `false`, the camera’s pitch
   * angle is ignored and the map is always displayed as if the user
   * is looking straight down onto it.
   */
  pitchEnabled: React.PropTypes.bool,
};

var RCTMap = requireNativeComponent('RCTMapper', MapView);

module.exports = MapView;

RCTMapManager.m

//
//  RCTMapManager.m
//  keyboardanim
//
//  Created by Dotan Nahum on 1/19/16.
//  Copyright © 2016 Facebook. All rights reserved.
//

#import <Foundation/Foundation.h>
// RCTMapManager.m
#import <MapKit/MapKit.h>

#import "RCTViewManager.h"
#import "RCTUIManager.h"

@interface RCTMapperManager : RCTViewManager
@end

@implementation RCTMapperManager

RCT_EXPORT_MODULE()

- (UIView *)view
{
  return [[MKMapView alloc] init];
}

RCT_EXPORT_VIEW_PROPERTY(pitchEnabled, BOOL)
RCT_EXPORT_METHOD(logstuff:(nonnull NSNumber *)reactTag
                  str:(NSString *)str)
{
  NSLog(@" with tag #%@", reactTag);
  [self.bridge.uiManager addUIBlock:
   ^(__unused RCTUIManager *uiManager, NSDictionary<NSNumber *, UIView *> *viewRegistry){
     UIView *view = viewRegistry[reactTag];
     NSLog(@" with view #%@", view);

   }];
}

@end