How to use google reverse geocoding with react native Expo?

Undestanding your requirement is completed with google api answer,

But now it is not for free, one cannot use more than free limit other than billing google account.

So, if you are or anyone working with React-Native-Geocoder , you can implement it like this:

var pos = {
  lat: 40.7809261,
  lng: -73.9637594
};

Geocoder.geocodePosition(pos).then(res => {
    alert(res[0].formattedAddress);
})
.catch(error => alert(error));

You don't need a library for reverse geocoding from LatLon, you can just call Google Maps API directly like:

fetch('https://maps.googleapis.com/maps/api/geocode/json?address=' + myLat + ',' + myLon + '&key=' + myApiKey)
        .then((response) => response.json())
        .then((responseJson) => {
            console.log('ADDRESS GEOCODE is BACK!! => ' + JSON.stringify(responseJson));
})

(remember to provide your Google Maps API Key!!)

The result object will have all the Address Components for that LatLon.

Example result

{"results":[{"address_components":[{"long_name":"540","short_name":"540","types":["street_number"]},{"long_name":"Avenida Alda Garrido","short_name":"Av. Alda Garrido","types":["route"]},{"long_name":"Barra da Tijuca","short_name":"Barra da Tijuca","types":["political","sublocality","sublocality_level_1"]},{"long_name":"Rio de Janeiro","short_name":"Rio de Janeiro","types":["administrative_area_level_2","political"]},{"long_name":"Rio de Janeiro","short_name":"RJ","types":["administrative_area_level_1","political"]},{"long_name":"Brazil","short_name":"BR","types":["country","political"]},{"long_name":"22640-000","short_name":"22640-000","types":["postal_code"]}],"formatted_address":"Av. Alda Garrido, 540 - Barra da Tijuca, Rio de Janeiro - RJ, 22640-000, Brazil","geometry":{"location":{"lat":-23.0077328,"lng":-43.315117},"location_type":"ROOFTOP","viewport":{"northeast":{"lat":-23.0063838197085,"lng":-43.3137680197085},"southwest":{"lat":-23.0090817802915,"lng":-43.3164659802915}}},"place_id":"ChIJfSac_7vQmwARNiQbMrnXe4E","types":["street_address"]},{"address_components":[{"long_name":"Apto 301","short_name":"Apto 301","types":["subpremise"]},{"long_name":"470","short_name":"470","types":["street_number"]},{"long_name":"Avenida Alda Garrido","short_name":"Av. Alda Garrido","types":["route"]},{"long_name":"Barra da Tijuca","short_name":"Barra da Tijuca","types":["political","sublocality","sublocality_level_1"]},{"long_name":"Rio de Janeiro","short_name":"Rio de Janeiro","types":["administrative_area_level_2","political"]},{"long_name":"Rio de Janeiro","short_name":"RJ","types":["administrative_area_level_1","political"]},{"long_name":"Brazil","short_name":"BR","types":["country","political"]},{"long_name":"22621-000","short_name":"22621-000","types":["postal_code"]}],"formatted_address":"Av. Alda Garrido, 470 - Apto 301 - Barra da Tijuca, Rio de Janeiro - RJ, 22621-000, Brazil","geometry":{"location":{"lat":-23.0079088,"lng":-43.3148068},"location_type":"ROOFTOP","viewport":{"northeast":{"lat":-23.0065598197085,"lng":-43.3134578197085},"southwest":{"lat":-23.0092577802915,"lng":-43.3161557802915}}},"place_id":"ChIJpQ8sq77QmwARA6fRe9QZWZ0","types":["establishment","lodging","point_of_interest"]},{"address_components":[{"long_name":"589","short_name":"589","types":["street_number"]},{"long_name":"Avenida Alda Garrido","short_name":"Av. Alda Garrido","types":["route"]},{"long_name":"Barra da Tijuca","short_name":"Barra da Tijuca","types":["political","sublocality","sublocality_level_1"]},{"long_name":"Rio de Janeiro","short_name":"Rio de Janeiro","types":["administrative_area_level_2","political"]},{"long_name":"Rio de Janeiro","short_name":"RJ","types":["administrative_area_level_1","political"]},{"long_name":"Brazil","short_name":"BR","types":["country","political"]},{"long_name":"22620-171","short_name":"22620-171","types":["postal_code"]}],"formatted_address":"Av. Alda Garrido, 589 - Barra da Tijuca, Rio de Janeiro - RJ, 22620-171, Brazil","geometry":{"location":{"lat":-23.0081304,"lng":-43.3147502},"location_type":"ROOFTOP","viewport":{"northeast":{"lat":-23.0067814197085,"lng":-43.3134012197085},"southwest":{"lat":-23.0094793802915,"lng":-43.3160991802915}}},"place_id":"ChIJr2eVq77QmwARA3U9jQNI5Z8","types":["establishment","premise"]},{"address_components":[{"long_name":"540","short_name":"540","types":["street_number"]},{"long_name":"Avenida Alda Garrido","short_name":"Av. Alda Garrido","types":["route"]},{"long_name":"Barra da Tijuca","short_name":"Barra da Tijuca","types":["political","sublocality","sublocality_level_1"]},{"long_name":"Rio de Janeiro","short_name":"Rio de Janeiro","types":["administrative_area_level_2","political"]},{"long_name":"Rio de Janeiro","short_name":"RJ","types":["administrative_area_level_1","political"]},{"long_name":"Brazil","short_name":"BR","types":["country","political"]},{"long_name":"22620-171","short_name":"22620-171","types":["postal_code"]}],"formatted_address":"Av. Alda Garrido, 540 - Barra da Tijuca, Rio de Janeiro - RJ, 22620-171, Brazil","geometry":{"location":{"lat":-23.0078265,"lng":-43.3151749},"location_type":"RANGE_INTERPOLATED","viewport":{"northeast":{"lat":-23.0064775197085,"lng":-43.3138259197085},"southwest":{"lat":-23.0091754802915,"lng":-43.3165238802915}}},"place_id":"EkRBdi4gQWxkYSBHYXJyaWRvLCA1NDAgLSBCYXJyYSBkYSBUaWp1Y2EsIFJpbyBkZSBKYW5laXJvIC0gUkosIEJyYXppbCIbEhkKFAoSCXvIbAC80JsAEXZMHH23Zf8TEJwE","types":["street_address"]},{"address_components":[{"long_name":"Avenida Alda Garrido","short_name":"Av. Alda Garrido","types":["route"]},{"long_name":"Barra da Tijuca","short_name":"Barra da Tijuca","types":["political","sublocality","sublocality_level_1"]},{"long_name":"Rio de Janeiro","short_name":"Rio de Janeiro","types":["administrative_area_level_2","political"]},{"long_name":"Rio de Janeiro","short_name":"RJ","types":["administrative_area_level_1","political"]},{"long_name":"Brazil","short_name":"BR","types":["country","political"]},{"long_name":"22620-171","short_name":"22620-171","types":["postal_code"]}],"formatted_address":"Av. Alda Garrido - Barra da Tijuca, Rio de Janeiro - RJ, 22620-171, Brazil","geometry":{"bounds":{"northeast":{"lat":-23.0077138,"lng":-43.3146692},"southwest":{"lat":-23.0080912,"lng":-43.3153903}},"location":{"lat":-23.0079025,"lng":-43.3150298},"location_type":"GEOMETRIC_CENTER","viewport":{"northeast":{"lat":-23.0065535197085,"lng":-43.3136807697085},"southwest":{"lat":-23.0092514802915,"lng":-43.3163787302915}}},"place_id":"ChIJe8hsALzQmwARd0wcfbdl_xM","types":["route"]},{"address_components":[{"long_name":"22620-400","short_name":"22620-400","types":["postal_code"]},{"long_name":"Barra da Tijuca","short_name":"Barra da Tijuca","types":["political","sublocality","sublocality_level_1"]},{"long_name":"Rio de Janeiro","short_name":"Rio de Janeiro","types":["administrative_area_level_2","political"]},{"long_name":"State of Rio de Janeiro","short_name":"RJ","types":["administrative_area_level_1","political"]},{"long_name":"Brazil","short_name":"BR","types":["country","political"]}],"formatted_address":"Barra da Tijuca, Rio de Janeiro - State of Rio de Janeiro, 22620-400, Brazil","geometry":{"bounds":{"northeast":{"lat":-23.0078347,"lng":-43.3137711},"southwest":{"lat":-23.0118196,"lng":-43.3149785}},"location":{"lat":-23.0108544,"lng":-43.3146249},"location_type":"APPROXIMATE","viewport":{"northeast":{"lat":-23.0078347,"lng":-43.31302581970849},"southwest":{"lat":-23.0118196,"lng":-43.31572378029149}}},"place_id":"ChIJxyn3hb7QmwARggN-wB930Xo","types":["postal_code"]},{"address_components":[{"long_name":"Barra da Tijuca","short_name":"Barra da Tijuca","types":["political","sublocality","sublocality_level_1"]},{"long_name":"Rio de Janeiro","short_name":"Rio de Janeiro","types":["administrative_area_level_2","political"]},{"long_name":"State of Rio de Janeiro","short_name":"RJ","types":["administrative_area_level_1","political"]},{"long_name":"Brazil","short_name":"BR","types":["country","political"]},{"long_name":"22620-171","short_name":"22620-171","types":["postal_code"]}],"formatted_address":"Barra da Tijuca, Rio de Janeiro - State of Rio de Janeiro, Brazil","geometry":{"bounds":{"northeast":{"lat":-23.0009429,"lng":-43.2977475},"southwest":{"lat":-23.0153102,"lng":-43.3294084}},"location":{"lat":-23.0093991,"lng":-43.3173933},"location_type":"APPROXIMATE","viewport":{"northeast":{"lat":-23.0009429,"lng":-43.2977475},"southwest":{"lat":-23.0153102,"lng":-43.3294084}}},"place_id":"ChIJ2zZsIqPQmwARquMCy3yno4Q","types":["postal_code","postal_code_prefix"]},{"address_components":[{"long_name":"Barra da Tijuca","short_name":"Barra da Tijuca","types":["political","sublocality","sublocality_level_1"]},{"long_name":"Rio de Janeiro","short_name":"Rio de Janeiro","types":["administrative_area_level_2","political"]},{"long_name":"State of Rio de Janeiro","short_name":"RJ","types":["administrative_area_level_1","political"]},{"long_name":"Brazil","short_name":"BR","types":["country","political"]}],"formatted_address":"Barra da Tijuca, Rio de Janeiro - State of Rio de Janeiro, Brazil","geometry":{"bounds":{"northeast":{"lat":-22.9642374,"lng":-43.2844897},"southwest":{"lat":-23.0228827,"lng":-43.45027049999999}},"location":{"lat":-23.0003709,"lng":-43.36589499999999},"location_type":"APPROXIMATE","viewport":{"northeast":{"lat":-22.9642374,"lng":-43.2844897},"southwest":{"lat":-23.0228827,"lng":-43.45027049999999}}},"place_id":"ChIJXf62J0ramwARTg-e2NH2w2M","types":["political","sublocality","sublocality_level_1"]},{"address_components":[{"long_name":"Rio de Janeiro","short_name":"Rio de Janeiro","types":["administrative_area_level_2","political"]},{"long_name":"State of Rio de Janeiro","short_name":"RJ","types":["administrative_area_level_1","political"]},{"long_name":"Brazil","short_name":"BR","types":["country","political"]}],"formatted_address":"Rio de Janeiro - State of Rio de Janeiro, Brazil","geometry":{"bounds":{"northeast":{"lat":-22.7460201,"lng":-43.0990395},"southwest":{"lat":-23.0828927,"lng":-43.7965385}},"location":{"lat":-22.9112301,"lng":-43.4452148},"location_type":"APPROXIMATE","viewport":{"northeast":{"lat":-22.7460201,"lng":-43.0990395},"southwest":{"lat":-23.0828927,"lng":-43.7965385}}},"place_id":"ChIJC7UkQv5-mQAR7llshDwliPk","types":["administrative_area_level_2","political"]},{"address_components":[{"long_name":"Rio de Janeiro","short_name":"Rio de Janeiro","types":["locality","political"]},{"long_name":"Rio de Janeiro","short_name":"Rio de Janeiro","types":["administrative_area_level_2","political"]},{"long_name":"State of Rio de Janeiro","short_name":"RJ","types":["administrative_area_level_1","political"]},{"long_name":"Brazil","short_name":"BR","types":["country","political"]}],"formatted_address":"Rio de Janeiro, State of Rio de Janeiro, Brazil","geometry":{"bounds":{"northeast":{"lat":-22.7460327,"lng":-43.0969042},"southwest":{"lat":-23.0822288,"lng":-43.7950599}},"location":{"lat":-22.9068467,"lng":-43.1728965},"location_type":"APPROXIMATE","viewport":{"northeast":{"lat":-22.7460327,"lng":-43.0969042},"southwest":{"lat":-23.0822288,"lng":-43.7950599}}},"place_id":"ChIJW6AIkVXemwARTtIvZ2xC3FA","types":["locality","political"]},{"address_components":[{"long_name":"State of Rio de Janeiro","short_name":"RJ","types":["administrative_area_level_1","political"]},{"long_name":"Brazil","short_name":"BR","types":["country","political"]}],"formatted_address":"State of Rio de Janeiro, Brazil","geometry":{"bounds":{"northeast":{"lat":-20.7632054,"lng":-40.9568207},"southwest":{"lat":-23.3689318,"lng":-44.8893205}},"location":{"lat":-22.9098755,"lng":-43.2094971},"location_type":"APPROXIMATE","viewport":{"northeast":{"lat":-20.7632054,"lng":-40.9568207},"southwest":{"lat":-23.3689318,"lng":-44.8893205}}},"place_id":"ChIJw4riypQYmAAR0IMFwRrDSQM","types":["administrative_area_level_1","political"]},{"address_components":[{"long_name":"Brazil","short_name":"BR","types":["country","political"]}],"formatted_address":"Brazil","geometry":{"bounds":{"northeast":{"lat":5.2717863,"lng":-28.650543},"southwest":{"lat":-34.0891,"lng":-73.9828169}},"location":{"lat":-14.235004,"lng":-51.92528},"location_type":"APPROXIMATE","viewport":{"northeast":{"lat":5.2717863,"lng":-28.650543},"southwest":{"lat":-34.0891,"lng":-73.9828169}}},"place_id":"ChIJzyjM68dZnAARYz4p8gYVWik","types":["country","political"]}],"status":"OK"}

There is Location.reverseGeocodeAsync(location) for expo app.