How can I assign value in "then" in Node JS in a global variable to use later

Question

let city;
let c;

async function getCity() {
  let apiKey = '9ddf7197ff9633535259c99aa0716c329981d1514f05e2e1e2015803';
  let response = await fetch(`https://api.ipdata.co?api-key=${apiKey}`);
  let data = await response.json();
  city = data.city;
  return city;
}

getCity().then(
    function (value) {
        c = value.city;
    },
    function (error) {
        console.log(error)
    }
);

console.log(c);

How do I assign a value to a global variable so that it can be use anywhere in the code. As I tried this method but I am getting "undefined" as my solution from console.log.

You can use window, window is a global object in the browser but you shouldn't use global variables at all — kevinSpaceyIsKeyserSöze, Nov 07 '22 at 15:01
You're assigning the value just fine to a global variable. The problem is that you attempt to use it immediately, not "later". This is why assigning variables asynchronously is a bad idea - you never know when they will have been assigned. — Bergi, Nov 07 '22 at 15:49

ajdejesus · Answer 1 · 2022-11-07T14:17:51.157

-1

I don't think you need to await when calling the function getCity(). I wasn't able to get a value, but I fixed the error. Try this:

let city;

async function getCity() {
  let apiKey = 'api_key';
  let response = await fetch(`https://api.ipdata.co?api-key=${apiKey}`);
  let data = await response.json();
  city = data.city;
  return city;
}

getCity().then(
    function (value) {
        console.log(value)
    },
    function (error) {
        console.log(error)
    }
);

edited Nov 07 '22 at 14:17

answered Nov 07 '22 at 14:10

ajdejesus

74
1
6

I am getting 'undefined' instead of the city name. – Prabhat Rai Nov 07 '22 at 14:12
1

@PrabhatRai Because the function doesn't return anything. – VLAZ Nov 07 '22 at 14:12
Then how do I get the solution. I am stuck with this and don't know what to do? – Prabhat Rai Nov 07 '22 at 14:17
Can you use the api key that I added and then try the code to get the city? – Prabhat Rai Nov 07 '22 at 14:20
@PrabhatRai worked for me with the API key – ajdejesus Nov 07 '22 at 14:21
I am getting 'undefined' instead of city name. – Prabhat Rai Nov 07 '22 at 14:22
@PrabhatRai Did you add the `return city;` at the end of the function? – ajdejesus Nov 07 '22 at 14:23
I didn't do it. It was not in the solution provided. But now I saw the edit. Thank you @ajdejesus – Prabhat Rai Nov 07 '22 at 14:26
But can you help me get it in a variable where I don't have to use "then" and use the variable later – Prabhat Rai Nov 07 '22 at 14:28
@PrabhatRai I'll try and get back with any update – ajdejesus Nov 07 '22 at 14:47
Ok but if you can hurry a bit then it would be helpful. Thank you once again for your help. – Prabhat Rai Nov 07 '22 at 14:52
It is difficult to set global variables with async functions, since the async function will always run after everything else has been executed. You can try the solutions stated here: https://stackoverflow.com/questions/59477505/set-value-of-global-variable-inside-async-function-or-inside-promise – ajdejesus Nov 07 '22 at 15:01

How can I assign value in "then" in Node JS in a global variable to use later

1 Answers1