Weather Forecast Service on Lambda Edge

index.js

const https = require("https");

const darksky_endpoint = 'https://api.darksky.net/forecast/37737016f7549777487b431061f4e220/';
const geocode_enpoint = 'https://maps.googleapis.com/maps/api/geocode/json?sensor=false&address=';

exports.handler = function(event, context, callback) {
    if (event.Records) {
        const request = event.Records[0].cf.request;
        getForecast(callback, request);
  }
}

const getForecast = function ( callback, request ) {
    let params = request.uri.split('/');
    params = params[params.length - 1];
    if (params) {
        params = encodeURI(params);
        Request(callback, ProcessGeoLocation, params, request, geocode_enpoint);
    }
}

const ProcessGeoLocation = function ( callback, request_event, response ) {
    const results = response.results[0];
    request_event.coords = {
        loc: results.address_components,
        lat: results.geometry.location.lat,
        lng: results.geometry.location.lng
    };
    const params = request_event.coords.lat + ',' + request_event.coords.lng;
    Request(callback, ProcessWeatherForecast, params, request_event, darksky_endpoint);
}

const ProcessWeatherForecast = function(callback, request_event, response) {
   const response_event = {
        status: '200',
        statusDescription: 'HTTP OK',
        httpVersion: request_event.httpVersion,
        body: JSON.stringify({
            weather: response.currently,
            location:  request_event.coords,
        }),
        headers: {
            'cache-control': [{
                key: 'Cache-Control',
                value: 'max-age=5'
            }],
             'content-type': [{
                key: 'Content-Type',
                value: 'application/json'
            }],
        },
    };
    callback(null, response_event);
}

let Request = function( callback, local_callback, params, request_event, endpoint ) {
    let request = https.get(endpoint + params, res => {
        let response = '';
        res.setEncoding("utf8");
        res.on("data", data => {
            response += data;
        });
        res.on("end", () => {
            response = JSON.parse(response);
            if (local_callback) {
                local_callback(callback, request_event, response);
            }
        });
        }).on('error', (e) => {
            console.error(e);
        });
}

const parseQueryString = function( queryString ) {
    let params = {}, queries, temp, i, l;
    // Split into key/value pairs
    queries = queryString.split("&");
    // Convert the array of strings into an object
    for ( i = 0, l = queries.length; i < l; i++ ) {
        temp = queries[i].split('=');
        params[temp[0]] = temp[1];
    }
    return params;
};