How to access nested arrays?

Question

I'm trying to access nested arrays in JavaScript from JSON returned from a weather app. However, I can't seem to access any of the data without the console returning cannot return property of 'x' of undefined. I'm fairly certain that the problem lies in how I am interacting with the result but I'm not sure. Does anyone know how I might properly access the data from within the nested array?

Here's my code that is currently not working:

const weather = require('weather-js');

var val;
var temp;
var final;

weather.find({search: 'Oceanside, CA', degreeType: 'F'}, function(err, result){         
  if (err) console.log(err);

  obj = JSON.stringify(result, null, 2);
  temp = result[2].current.temperature;
  console.log(temp);
  final = result[1].location.name;
  console.log(final)
});

And here is the JSON I am trying to interact with:

[
  {
    "location": {
      "name": "Oceanside, CA",
      "lat": "33.197",
      "long": "-117.381",
      "timezone": "-8",
      "alert": "",
      "degreetype": "F",
      "imagerelativeurl": "http://blob.weather.microsoft.com/static/weather4/en-us/"
    },
    "current": {
      "temperature": "55",
      "skycode": "31",
      "skytext": "Mostly Clear",
      "date": "2018-12-18",
      "observationtime": "22:15:00",
      "observationpoint": "Oceanside, CA",
      "feelslike": "55",
      "humidity": "90",
      "winddisplay": "3 mph Southwest",
      "day": "Tuesday",
      "shortday": "Tue",
      "windspeed": "3 mph",
      "imageUrl": "http://blob.weather.microsoft.com/static/weather4/en-us/law/31.gif"
    },
    "forecast": [
      {
        "low": "46",
        "high": "64",
        "skycodeday": "29",
        "skytextday": "Partly Cloudy",
        "date": "2018-12-17",
        "day": "Monday",
        "shortday": "Mon",
        "precip": ""
      },
      {
        "low": "45",
        "high": "65",
        "skycodeday": "34",
        "skytextday": "Mostly Sunny",
        "date": "2018-12-18",
        "day": "Tuesday",
        "shortday": "Tue",
        "precip": "0"
      },
      {
        "low": "44",
        "high": "67",
        "skycodeday": "34",
        "skytextday": "Mostly Sunny",
        "date": "2018-12-19",
        "day": "Wednesday",
        "shortday": "Wed",
        "precip": "0"
      },
      {
        "low": "47",
        "high": "69",
        "skycodeday": "30",
        "skytextday": "Partly Sunny",
        "date": "2018-12-20",
        "day": "Thursday",
        "shortday": "Thu",
        "precip": "0"
      },
      {
        "low": "47",
        "high": "65",
        "skycodeday": "34",
        "skytextday": "Mostly Sunny",
        "date": "2018-12-21",
        "day": "Friday",
        "shortday": "Fri",
        "precip": "0"
      }
    ]
  }
]

This question is not a duplicate of Access / process (nested) objects, arrays or JSON because as far as I can see the answers on that page dealt with arrays of more than a single element and this question did not.

`cannot return property of 'x' of undefined` There is no `x` in the code in your question though, what line does that error appear on? (that sounds like a paraphrased error, not the actual error - please post the actual error) — CertainPerformance, Dec 19 '18 at 07:57
It doesn't actually say 'x'. It says either current or location if we're being specific. X is just for the sake of simplicity. — Kelsey R., Dec 19 '18 at 07:58
You have an array of **_single_** element in `result`. That's why you get error on `result[2].*` — hindmost, Dec 19 '18 at 08:00
well your result array is having only one element. which is an object and you're trying to access elements at index other than zero. — Code Maniac, Dec 19 '18 at 08:00
This question has nothing to do with JSON per se. Apart from the unused(!) `obj`, there’s no JSON anywhere. — Biffen, Dec 19 '18 at 08:02
Possible duplicate of [Access / process (nested) objects, arrays or JSON](https://stackoverflow.com/questions/11922383/access-process-nested-objects-arrays-or-json) — Biffen, Dec 19 '18 at 08:04

score 0 · Accepted Answer · edited Dec 19 '18 at 08:06

//try this its working
var j = [{
  "location": {
    "name": "Oceanside, CA",
    "lat": "33.197",
    "long": "-117.381",
    "timezone": "-8",
    "alert": "",
    "degreetype": "F",
    "imagerelativeurl": "http://blob.weather.microsoft.com/static/weather4/en-us/"
  },
  "current": {
    "temperature": "55",
    "skycode": "31",
    "skytext": "Mostly Clear",
    "date": "2018-12-18",
    "observationtime": "22:15:00",
    "observationpoint": "Oceanside, CA",
    "feelslike": "55",
    "humidity": "90",
    "winddisplay": "3 mph Southwest",
    "day": "Tuesday",
    "shortday": "Tue",
    "windspeed": "3 mph",
    "imageUrl": "http://blob.weather.microsoft.com/static/weather4/en-us/law/31.gif"
  },
  "forecast": [{
      "low": "46",
      "high": "64",
      "skycodeday": "29",
      "skytextday": "Partly Cloudy",
      "date": "2018-12-17",
      "day": "Monday",
      "shortday": "Mon",
      "precip": ""
    },
    {
      "low": "45",
      "high": "65",
      "skycodeday": "34",
      "skytextday": "Mostly Sunny",
      "date": "2018-12-18",
      "day": "Tuesday",
      "shortday": "Tue",
      "precip": "0"
    },
    {
      "low": "44",
      "high": "67",
      "skycodeday": "34",
      "skytextday": "Mostly Sunny",
      "date": "2018-12-19",
      "day": "Wednesday",
      "shortday": "Wed",
      "precip": "0"
    },
    {
      "low": "47",
      "high": "69",
      "skycodeday": "30",
      "skytextday": "Partly Sunny",
      "date": "2018-12-20",
      "day": "Thursday",
      "shortday": "Thu",
      "precip": "0"
    },
    {
      "low": "47",
      "high": "65",
      "skycodeday": "34",
      "skytextday": "Mostly Sunny",
      "date": "2018-12-21",
      "day": "Friday",
      "shortday": "Fri",
      "precip": "0"
    }
  ]
}];
console.log(j[0].current.temperature);
console.log(j[0].location.name);

score 0 · Answer 2 · answered Dec 19 '18 at 08:09

It's pretty simple. Say an array in JavaScript is defined as var myArray=[]

You will notice that your JSON has an outer [] and in this you have 1 outer {}, meaning it has 1 element in the array at index 0.

So, instead of doing result[2].current.temperature; just do result[0].current.temperature;

using result[2] will give you undefined since it does not exist!

How to access nested arrays?

2 Answers2