Why can I not parse json string using jQuery.parseJSON(json)?

Question

I am trying to parse a response of a string which is a json string. In another page of my web app following code is working fine. but its not working for my current page i am working with. Following is the code:

 $.ajax({
    type: 'POST',
    url: 'http://mywebapp.com/sendnames',
    data: {},
    success: function(result) {
        alert('result: '+result);
        var obj = jQuery.parseJSON(result);
        alert('obj: '+obj);

    // doing rest of stuff  
    }

});

first alert comes and shows right result. result is:

 [
   "Richard",
   "Eric",
   "John"
 ]

but second alert does not come. i checked it, its a valid json. why can not i parse this json with jQuery.parseJSON(). Thanks in advance.

It's probably because jQuery has already checked the type and your result is a JSON object already. Try alerting the typeof result and seeing what you get. Or accessing one of the expected properties. — Alex
– Alex, Commented Aug 31, 2012 at 8:22
@Musa no that alert does not come. thats why i wrote jQuery.parseJSON is not working. — Piscean
– Piscean, Commented Aug 31, 2012 at 8:22
i am getting the response i want. i debug jquery using alerts. did not get which console are you talking about? — Piscean
– Piscean, Commented Aug 31, 2012 at 8:27
I agree with Alex and do a console.log instead of alert. Console.log(result).Let us know the result — Nick
– Nick, Commented Aug 31, 2012 at 8:27

Oyeme · Accepted Answer · 2012-08-31 08:53:52Z

Try to add return type: dataType : json

$.ajax({
        type: 'POST',
        url: 'http://mywebapp.com/sendnames',
        data: {},
        dataType:'json',
        success: function(result) {
          console.log('result: '+result);        
        // doing rest of stuff  
        }

    });

"json":
Evaluates the response as JSON and returns a JavaScript object. In jQuery 1.4 the JSON data is parsed in a strict manner; any malformed JSON is rejected and a parse error is thrown. (See json.org for more information on proper JSON formatting.) "jsonp": Loads in a JSON block using JSONP. Adds an extra "?callback=?" to the end of your URL to specify the callback. Disables caching by appending a query string parameter, "_=[TIMESTAMP]", to the URL unless the cache option is set to true. http://api.jquery.com/jQuery.ajax/

jQuery.parseJSON is still wrong, because dataType:json will cause jQuery do that internally. The result variable will already contain a JS object.

Stefan Majewsky · Accepted Answer · 2012-08-31 08:32:06Z

1

Replace $.ajax by $.getJSON. This is guaranteed to trigger $.parseJSON internally, so result will already be the desired JS object.

$.getJSON({
   type: 'POST',
   url: 'http://mywebapp.com/sendnames',
   data: {},
   success: function(obj) {
      alert('obj: '+obj);
      // doing rest of stuff  
   }
});

answered Aug 31, 2012 at 8:32

Stefan Majewsky

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Comments

Yograj Gupta · Accepted Answer · 2012-08-31 08:36:30Z

0

Try with adding dataType:'text', it will return string as result. and your code will run as you expect.

answered Aug 31, 2012 at 8:36

Yograj Gupta

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Community · Accepted Answer · 2017-05-23 12:12:20Z

0

See the accepted answer here

You're parsing an object. You parse strings, not objects; jQuery.parseJSON only takes strings.

Because $.ajax already parsed the data, result is Javascript object not a string. parseJSON expects a string parameter.

FROM DOCS (more on .ajax() data types here):

The json type parses the fetched data file as a JavaScript object and returns the constructed object as the result data. To do so, it uses jQuery.parseJSON() when the browser supports it; otherwise it uses a Function constructor

.

edited May 23, 2017 at 12:12

CommunityBot

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answered Aug 31, 2012 at 8:39

robasta

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2 Comments

Harsh Baid Over a year ago

in your answer stackoverflow.com/questions/8631977/… the json object was declared and intialized client-side here the case is not the same i.e. here the resultant object is from external ajax calls which can be anything !!

robasta Over a year ago

I'm guessing http://mywebapp.com/sendnames returns the mime type as JSON, and therefore JQuery.parseJSON() is run on the data automatically by jquery.

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