Error when trying to store JSON data in variable

Question

I am trying to show some JSON data on my website from external URL. When run the script I get this error from the chrome console:

Uncaught SyntaxError: Unexpected token u in JSON at position 0 at JSON.parse ()

Javascript:

var json = $.getJSON("url");

var a = JSON.parse(json.responseText);

var result = a.query.results.rate;

document.write(result[0].Rate);

When I type console.log(result) in the console it returns undefined

JSON:

{
"query": {
    "count": 6,
    "created": "2016-12-21T19:18:22Z",
    "lang": "en-US",
    "diagnostics": {
        "url": [{
                "execution-start-time": "1",
                "execution-stop-time": "2",
                "execution-time": "1",
                "content": "url"
            }, {
                "execution-start-time": "5",
                // more of this
            ]

            "results": {
                "rate": [{
                        "id": "GBPUSD",
                        "Name": "GBP/USD",
                        "Rate": "1.2371",
                    },

                    {
                        "id": "GBPEUR",
                        // more of this
                    },

                }
            ]
        }

I can't make any changes on the JSON file, but I checked it and it is valid.

P.S. When I write the JavaScript code in the chrome console it works.

Thanks in advance.

I just ran the sample JSON through [jsbeautifier.org](http://jsbeautifier.org/) - it looks like the outer json object isn't quite closed properly... — Sᴀᴍ Onᴇᴌᴀ, Dec 21 '16 at 19:43
Did you try to put a "?callback=" string at the end of your request URL? — Pablo Darde, Dec 21 '16 at 19:45

score 3 · Accepted Answer · answered Dec 21 '16 at 19:43

3

Here's your problem:

var json = $.getJSON("url");

This is an asynchronous operation, you need to give it time to load, something like this would work:

$.getJSON("url").done(function(response) {
    var result = response.query.results.rate;
    document.write(result[0].Rate);
});

answered Dec 21 '16 at 19:43

Tompina

726
1
9
25

1

Thanks very much it works! – hml Dec 21 '16 at 19:56

Billy Moon · Answer 2 · 2016-12-21T19:47:00.777

0

It will work in the console if you execute each line with a bit of time in between AS response will have had time to complete and populate responseText. You need to rite the main code in a callback or promise chain after $.getJSON has completed.

Perhaps...

$.getJSON("url").then(function(data){
    var result = data.query.results.rate;
    document.write(result[0].Rate);
});

edited Dec 21 '16 at 19:47

answered Dec 21 '16 at 19:41

Billy Moon

57,113
24
136
237

Thanks very much it works too! – hml Dec 21 '16 at 19:56

Error when trying to store JSON data in variable

2 Answers2