iNaturalistReactNative/src/sharedHelpers/fetchPlaceName.js

// @flow

import NetInfo from "@react-native-community/netinfo";
import Geocoder from "react-native-geocoder-reborn";

// lifted from SeekReactNative repo
const setPlaceName = ( results: Array<Object> ): string => {
  let placeName = "";

  const {
    streetName, locality, adminArea, countryCode
  } = results[0];
  // we could get as specific as sublocality here, but a lot of the results are
  // too specific to be helpful in the U.S. at least. neighborhoods, parks, etc.

  // this seems to be preferred formatting for iNat web
  // TODO: localize formatting
  // TODO: throttle requests on iOS so this doesn't error out in location picker
  const appendName = name => ( placeName.length > 0
    ? `, ${name}`
    : name );

  if ( streetName ) {
    placeName += streetName;
  }
  if ( locality ) {
    placeName += appendName( locality );
  }
  if ( adminArea ) {
    placeName += appendName( adminArea );
  }
  if ( countryCode ) {
    placeName += appendName( countryCode );
  }
  return placeName;
};

const fetchPlaceName = async ( lat: ?number, lng: ?number ): Promise<?string> => {
  if ( !lat || !lng ) { return null; }
  const { isConnected } = await NetInfo.fetch( );
  if ( !isConnected ) { return null; }
  try {
    const results = await Geocoder.geocodePosition( { lat, lng } );
    if ( results.length === 0 || typeof results !== "object" ) { return null; }
    return setPlaceName( results );
  } catch ( geocoderError ) {
    if ( !geocoderError?.message?.includes( "geocodePosition failed" ) ) throw geocoderError;
    return null;
  }
};

export default fetchPlaceName;