A pubnub block for converting lat/lon to an address

esri_reverse_geocoding_input

/*
    This ArcGIS-based PubNub Block shows a pattern for converting a lat/lon coordinate to an address

    Declare the Event Handler with the export syntax. The incoming message is called request.
    
    Set up the test payload
    {
      "lat": -105.521,
      "lon": 40.377
    }
    
*/
export default (request) => {
    let xhr = require('xhr');
    let query = require('codec/query_string');
    const console = require('console');
    
    // one off geocoding requests do not require authentication if the results are *not* stored
    // https://developers.arcgis.com/rest/geocode/api-reference/geocoding-free-vs-paid.htm
    
    let apiUrl = 'https://geocode.arcgis.com/arcgis/rest/services/World/GeocodeServer/reverseGeocode';
    let searchParam = request.message;

    // return if the block does not have anything to analyze
    if (!query) {
        return request.ok();
    }
    
    let queryParams = {
        location: searchParam.lat + ", " + searchParam.lon,
        f: 'json'
    };

    let url = apiUrl + '?' + query.stringify(queryParams);
    
    return xhr.fetch(url)
        .then((response) => {
            return response.json()
                .then((parsedResponse) => {
                    request.message.geocode = parsedResponse;
                    console.log("Ouput: " + request.message.geocode.address.Address);
                    return request;
                })
                .catch((err) => {
                    console.log('error happened on JSON parse', err);
                    return request;
                });
        })
        .catch((err) => {
            console.log('error happened for XHR.fetch', err);
            return request;
        });
};