Set initial region on view (react-native-maps#1579)

Author: petha

lib/ios/AirMaps/AIRMapManager.m

@@ -97,7 +97,17 @@ - (UIView *)view
 RCT_EXPORT_VIEW_PROPERTY(onMarkerDrag, RCTDirectEventBlock)
 RCT_EXPORT_VIEW_PROPERTY(onMarkerDragEnd, RCTDirectEventBlock)
 RCT_EXPORT_VIEW_PROPERTY(onCalloutPress, RCTDirectEventBlock)
-RCT_EXPORT_VIEW_PROPERTY(initialRegion, MKCoordinateRegion)
+RCT_CUSTOM_VIEW_PROPERTY(initialRegion, MKCoordinateRegion, AIRMap)
+{
+    if (json == nil) return;
+
+    // don't emit region change events when we are setting the initialRegion
+    BOOL originalIgnore = view.ignoreRegionChanges;
+    view.ignoreRegionChanges = YES;
+    [view setInitialRegion:[RCTConvert MKCoordinateRegion:json]];
+    view.ignoreRegionChanges = originalIgnore;
+}
+
 RCT_EXPORT_VIEW_PROPERTY(minZoomLevel, CGFloat)
 RCT_EXPORT_VIEW_PROPERTY(maxZoomLevel, CGFloat)
 
@@ -665,7 +675,7 @@ - (void)mapViewDidFinishRenderingMap:(AIRMap *)mapView fullyRendered:(BOOL)fully
 {
     [mapView finishLoading];
     [mapView cacheViewIfNeeded];
-    
+
     mapView.onMapReady(@{});
 }