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JavaScript

Ryan Doyle
Ryan Doyle
8,587 Points
Posted by Ryan Doyle
Ryan Doyle
8,587 Points

Cannot access values of JSON objects

I'm having an issue with the following code:

weather.js 
function printCurrent(location, time, temp) {
    const message = `In ${location} it is currently ${temp}. As of: ${time}`;
    console.log(message)
}

const https = require('https');
const http = require('http');
const api = require('./api.json');


function get(location) {
    const req = https.get(`https://api.wunderground.com/api/${api.key}/forecast/conditions/q/${location}.json`, response => {
        let body = "";
        response.on('data', data => {
            body += data.toString(); // adds to body each time a data packet is received
        });
        response.on('end', data => {
            const forecast = JSON.parse(body);
            console.log(forecast.current_observation.display_location.full);
        });    
    })
}

get();
module.exports.getLocation = get;

I cannot seem to access any of the actual data from the "forecast" object. I can get the type of as an object, and print out the forecast and it looks like an object, but then if I try to access anything, I get: "TypeError: Cannot read property 'display_location' of undefined"

I believe it has to do with the fact that it seems to return 2 objects. (If I do typeof forecast, I get 2 objects). But I'm not sure why that's happening either :/

2 Answers

Myers Carpenter
Myers Carpenter
6,421 Points
Myers Carpenter
Myers Carpenter
6,421 Points

You are really close, let's see if I can give you a nudge:

I ran your code and got 

/Users/myers/forum/weather.js:19
            console.log(forecast.current_observation.display_location.full);
                                                    ^

TypeError: Cannot read property 'display_location' of undefined
    at IncomingMessage.response.on.data (/Users/myers/forum/weather.js:19:53)
    at emitNone (events.js:110:20)
    at IncomingMessage.emit (events.js:207:7)
    at endReadableNT (_stream_readable.js:1059:12)
    at _combinedTickCallback (internal/process/next_tick.js:138:11)
    at process._tickCallback (internal/process/next_tick.js:180:9)

so let's explore what is in the forecast variable, with console.log(forecast);

{ response:
   { version: '0.1',
     termsofService: 'http://www.wunderground.com/weather/api/d/terms.html',
     features: { forecast: 1, conditions: 1 },
     error:
      { type: 'querynotfound',
        description: 'No cities match your search query' } } }

Ok, so we called get() with no arguments and that meant we didn't ask for any location, what if we do get("IAD") (that's Washington Dulles International, VA), and IT WORKS!

{ response:
   { version: '0.1',
     termsofService: 'http://www.wunderground.com/weather/api/d/terms.html',
     features: { forecast: 1, conditions: 1 } },
  current_observation:
   { image:
      { url: 'http://icons.wxug.com/graphics/wu2/logo_130x80.png',
        title: 'Weather Underground',
        link: 'http://www.wunderground.com' },
     display_location:
      { full: 'Washington Dulles International, VA',
        city: 'Washington Dulles International',
        state: 'VA',
        state_name: 'Virginia',
        country: 'US',
        country_iso3166: 'US',
        zip: '20101',
        magic: '5',
        wmo: '99999',
        latitude: '38.94444275',
        longitude: '-77.45555878',
        elevation: '95.0' },
     observation_location:
      { full: 'Dulles Airport, Virginia',
        city: 'Dulles Airport',
        state: 'Virginia',
        country: 'US',
        country_iso3166: 'US',
        latitude: '38.93999863',
        longitude: '-77.45999908',
        elevation: '312 ft' },
     estimated: {},
     station_id: 'KIAD',
     observation_time: 'Last Updated on February 19, 3:00 PM EST',
     observation_time_rfc822: 'Mon, 19 Feb 2018 15:00:00 -0500',
     observation_epoch: '1519070400',
     local_time_rfc822: 'Mon, 19 Feb 2018 15:29:04 -0500',
     local_epoch: '1519072144',
     local_tz_short: 'EST',
     local_tz_long: 'America/New_York',
     local_tz_offset: '-0500',
     weather: 'Light Drizzle',
     temperature_string: '46 F (8 C)',
     temp_f: 46,
     temp_c: 8,
     relative_humidity: '96%',
     wind_string: 'From the SSE at 12 MPH',
     wind_dir: 'SSE',
     wind_degrees: 160,
     wind_mph: 12,
     wind_gust_mph: 0,
     wind_kph: 18,
     wind_gust_kph: 0,
     pressure_mb: '1027',
     pressure_in: '30.33',
     pressure_trend: '-',
     dewpoint_string: '45 F (7 C)',
     dewpoint_f: 45,
     dewpoint_c: 7,
     heat_index_string: 'NA',
     heat_index_f: 'NA',
     heat_index_c: 'NA',
     windchill_string: '41 F (5 C)',
     windchill_f: '41',
     windchill_c: '5',
     feelslike_string: '41 F (5 C)',
     feelslike_f: '41',
     feelslike_c: '5',
     visibility_mi: '3.0',
     visibility_km: '4.8',
     solarradiation: '--',
     UV: '1',
     precip_1hr_string: '0.00 in (0.0 mm)',
     precip_1hr_in: '0.00',
     precip_1hr_metric: '0.0',
     precip_today_string: '0.04 in (1.0 mm)',
     precip_today_in: '0.04',
     precip_today_metric: '1.0',
     icon: 'rain',
     icon_url: 'http://icons.wxug.com/i/c/k/rain.gif',
     forecast_url: 'http://www.wunderground.com/US/VA/Washington_Dulles_International.html',
     history_url: 'http://www.wunderground.com/history/airport/KIAD/2018/2/19/DailyHistory.html',
     ob_url: 'http://www.wunderground.com/cgi-bin/findweather/getForecast?query=38.93999863,-77.45999908',
     nowcast: '' },
  forecast:
   { txt_forecast: { date: '2:27 PM EST', forecastday: [Array] },
     simpleforecast: { forecastday: [Array] } } }
Washington Dulles International, VA
Ryan Doyle
Ryan Doyle
8,587 Points
Ryan Doyle
Ryan Doyle
8,587 Points

Thanks! Yes, I realized it was calling get() twice. I had just the get() and then in another linked file, I was actually using the terminal to call get() again but with an argument. The empty one would always finish first and get me that first object.