I parse few data using a type class in my controller I'm getting data as follows:
{
"data":{
"userList":[
{
"id":1,
"name":"soni"
}
]
},
"status":200,
"config":{
"method":"POST",
"transformRequest":[
null
],
"transformResponse":[
null
],
"url":"/home/main/module/userlist",
"headers":{
"rt":"ajax",
"Tenant":"Id:null",
"Access-Handler":"Authorization:null",
"Accept":"application/json, text/plain, */*"
}
},
"statusText":"OK"
}
I tried to store the data like this
var userData = _data;
var newData = JSON.parse(userData).data.userList;
How can I extract the user list to a new variable?
This question is related to
javascript
angularjs
json
The JSON you posted looks fine, however in your code, it is most likely not a JSON string anymore, but already a JavaScript object. This means, no more parsing is necessary.
You can test this yourself, e.g. in Chrome's console:
new Object().toString()
// "[object Object]"
JSON.parse(new Object())
// Uncaught SyntaxError: Unexpected token o in JSON at position 1
JSON.parse("[object Object]")
// Uncaught SyntaxError: Unexpected token o in JSON at position 1
JSON.parse() converts the input into a string. The toString() method of JavaScript objects by default returns [object Object], resulting in the observed behavior.
Try the following instead:
var newData = userData.data.userList;
Well, I meant that I need to parse object like this: var jsonObj = {"first name" : "fname"}. But, I don't actually. Because it's already an JSON.
Unexpected 'O' error is thrown when JSON data or String happens to get parsed.
If it's string, it's already stringfied. Parsing ends up with Unexpected 'O' error.
I faced similar( although in different context), I solved the following error by removing JSON Producer.
@POST
@Produces({ **MediaType.APPLICATION_JSON**})
public Response login(@QueryParam("agentID") String agentID , Officer aOffcr ) {
return Response.status(200).entity("OK").build();
}
The response contains "OK" string return. The annotation marked as @Produces({ **MediaType.APPLICATION_JSON})** tries to parse the string to JSON format which results in Unexpected 'O'.
Removing @Produces({ MediaType.APPLICATION_JSON}) works fine. Output : OK
Beware: Also, on client side, if you make ajax request and use JSON.parse("OK"), it throws Unexpected token 'O'
O is the first letter of the string
JSON.parse(object) compares with jQuery.parseJSON(object);
JSON.parse('{ "name":"Yergalem", "city":"Dover"}'); --- Works Fine
the first parameters of function JSON.parse should be a String, and your data is a JavaScript object, so it will convert to a String [object object], you should use JSON.stringify before pass the data
JSON.parse(JSON.stringify(userData))
var data = JSON.parse(userData); console.log(data);
Give a try catch like this, this will parse it if its stringified or else will take the default value
let example;
try {
example = JSON.parse(data)
} catch(e) {
example = data
}
We can also add checks like this:
function parseData(data) {
if (!data) return {};
if (typeof data === 'object') return data;
if (typeof data === 'string') return JSON.parse(data);
return {};
}
You can simply check the typeof userData & JSON.parse() it only if it's string:
var userData = _data;
var newData;
if (typeof userData === 'object')
newData = userData.data.userList; // dont parse if its object
else if (typeof userData === 'string')
newData = JSON.parse(userData).data.userList; // parse if its string
Just above JSON.parse, use:
var newData = JSON.stringify(userData)
Don't ever use JSON.parse without wrapping it in try-catch block:
// payload
let userData = null;
try {
// Parse a JSON
userData = JSON.parse(payload);
} catch (e) {
// You can read e for more info
// Let's assume the error is that we already have parsed the payload
// So just return that
userData = payload;
}
// Now userData is the parsed result
Source: Stackoverflow.com