Can`t use the response from a get request using callback function

Question

I make a get request from a url, and I try to use the response further, in another function, so this is what I tried first.

var request = require("request");

function getJSON(getAddress) {
    request.get({
        url: getAddress,
        json: true,
    }, function (error, response, body) {
        if (!error && response.statusCode == 200) {
            return body;
        }
     })
 }

function showJSON(getAddress, callback) {
    var test = callback(getAddress);
    console.dir(test);
}

showJSON('http://api.open-notify.org/astros.json', getJSON);

yet, when i run my script

node ./test.js

I get

'undefined' as a console message

I don`t know where this may come from, as I am new to node.js, javascript

As I said, I am noy sure at all where this comes from. I would check this, hope it will answer my question. thank you — Mirel Ionut Puchianu, Aug 21 '17 at 07:59

marvel308 · Accepted Answer · 2017-08-21T08:04:53.090

1

var test = callback(getAddress);

is an asynchronous function

console.dir(test);

won't wait for it to finish before executing, hence you are getting undefined. to make it work you would have to do

var request = require("request");

function getJSON(getAddress, callback) {
    request.get({
        url: getAddress,
        json: true,
    }, function (error, response, body) {
        if (!error && response.statusCode == 200) {
            callback(body);
        }
     })
 }

function showJSON(getAddress, callback) {
    callback(getAddress, function(test){
        console.dir(test);
    });
}

showJSON('http://api.open-notify.org/astros.json', getJSON);

edited Aug 21 '17 at 08:04

answered Aug 21 '17 at 07:59

marvel308

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Any idea how can I modify my code to work? – Mirel Ionut Puchianu Aug 21 '17 at 08:02
@MirelIonutPuchianu Did you even took a look at the link I provided ? The answer is inside... (Hint : look at the accepted answer). – Serge K. Aug 21 '17 at 08:04
I edited the answer to be able to print the value of test – marvel308 Aug 21 '17 at 08:05
I was looking through it when marvel answered me, @NathanP. – Mirel Ionut Puchianu Aug 21 '17 at 08:17

Can`t use the response from a get request using callback function

1 Answers1