Unexpected token u in JSON at position 0 when trying to access a field of JSON

Question

The following is the json that I am receiving:

{
"total": 5,
"responses": [{
    "gender": "Female",
    "age": 66
}, {
    "gender": "Male",
    "age": 52
}]
}

The following is the code I am using to receive and parse the json

// Declare a proxy to reference the hub.
$.connection.hub.url = 'https://www.url...';
var res = $.connection.resHub;
// Create a function that the hub can call to broadcast messages.
res.client.broadcastRes = function (resp) {
 var now = new Date();
 console.log(now.toLocaleTimeString(), 'signalR survey data received', JSON.parse(resp));
 createChart(JSON.parse(resp.responses));
};
$.connection.hub.start();

In the console I am being able to see the entire JSON response like I showed above by doing console.log(JSON.parse(resp));

But I am getting the error

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

When I am using resp.responses

Where am I going wrong?

Any kind of help would be greatly appreciated. Thanks.

`resp.responses` is `undefined` - hence the unexpected `u` as `undefined` gets stringified. — Kirk Larkin, Mar 15 '18 at 15:15
Possible duplicate of [I keep getting "Uncaught SyntaxError: Unexpected token o"](https://stackoverflow.com/questions/8081701/i-keep-getting-uncaught-syntaxerror-unexpected-token-o) — Heretic Monkey, Mar 15 '18 at 15:15
Check [**morgane1806 answer**](https://stackoverflow.com/a/49303106/448144) below. Even with lack of explanation it is most likely what you looking for. — Nope, Mar 15 '18 at 15:22
Apologies, that was the incorrect duplicate. It should be [Uncaught SyntaxError: Unexpected token u in JSON at position 0](//stackoverflow.com/q/46613243) — Heretic Monkey, Mar 15 '18 at 15:42

score 1 · Answer 1 · answered Mar 15 '18 at 15:14

1

Try this : createChart(JSON.parse(resp).responses);

answered Mar 15 '18 at 15:14

morgane1806

75
1
5

2

Could you add some explanation? What went wrong before and what you did to fix it. This was flagged as a low quality answer – Huangism Mar 15 '18 at 16:13

score 0 · Accepted Answer · answered Mar 15 '18 at 15:19

0

Well, basically, if resp is an string, then if you do JSON.parse(resp.responses) will fail because responses is undefined.

You just want JSON.parse(resp).responses. This contains the array you need

answered Mar 15 '18 at 15:19

Oscar Paz

18,084
3
27
42

Unexpected token u in JSON at position 0 when trying to access a field of JSON

2 Answers2