Converting string to a valid JSON object

Question

hey there i saw many questions about this topic but none of them fit my question. i'm trying to use localStorage to store a user custom preferences, i try put an json object into a localStorage key and use it later on. the object at the beginning looks like that:

 Object {test: "{a:"b",c:"d"}"}

the JSON.parse method returns an error, what i done is that:

var local_storage = getAll();
$.parseJSON(JSON.stringify(local_storage.test.substring(0,0).substring(0,local_storage.length,-1)));

the output is :

{a:"b",c:"d"}

but i can't use it as local_storage.test.a why is that and what is the solution for that?

thx for the help :)

Edit!

Thanks to @Oli Soproni B, the solution is:

var key = {a:"b",c:"d"};
var l = JSON.stringify(key);
localStorage.setItem('test',l);
var local_storage = $.parseJSON(localStorage.getItem('test'));
console.log(local_storage);
console.log(local_storage.a);

what is local_storage.test.substring(0,0).substring(0,local_storage.length,-1)? — Arun P Johny
– Arun P Johny, Commented Feb 17, 2015 at 8:17

Oli Soproni B. · Accepted Answer · 2015-02-17 08:43:30Z

3

// data
    var k = {a:"b", c: "d"};
    // stringify json
    var l = JSON.stringify(k);
    // set item to local storage
    localStorage.setItem('test', l);

    // get item to local storage and parse data
    var local_storage = $.parseJSON(localStorage.getItem('test'));

    console.log(local_storage);

    Object {a: "b", c: "d"}

    console.log(local_storage.a);

    prints b

// or use 
 var local_storage = JSON.parse(localStorage.getItem('test'));
// in parsing the stringify json data

edited Feb 17, 2015 at 8:43

answered Feb 17, 2015 at 8:29

Oli Soproni B.

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1 Comment

skobaljic Over a year ago

Since you use JSON.stringify, than you should also use JSON.parse, no need for jQuery here. jQuery would return same anyway: if ( window.JSON && window.JSON.parse ) {return window.JSON.parse( data + "" );}

codingrose · Accepted Answer · 2015-02-17 08:33:41Z

1

Localstorage stores string, not object. So you need to convert object to string while storing and converting it to object while retrieving.

To store:

localStorage.setItem("key",JSON.stringify(obj));

To retrieve:

obj = JSON.parse(localStorage.getItem(obj));

See DEMO here.

edited Feb 17, 2015 at 8:33

answered Feb 17, 2015 at 8:26

codingrose

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Comments

Naeem Shaikh · Accepted Answer · 2015-02-17 08:21:44Z

0

You used Json.stringify, because you need to store the data into localstorage as a string only.

you need to parse that again to JSON in order to use it as a JSON object,

but not like this

JSON.stringify(local_storage.test.substring(0,0).substring(0,local_storage.length,-1))

This tries to get a substring from your previously stored string, and again tries to stringify it.

You can get the stored string directly like this,

var local_storage = getAll();
var test=JSON.parse(local_storage.test);

And then use, as the test object, as test: {a:"b",c:"d"}

answered Feb 17, 2015 at 8:21

Naeem Shaikh

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1 Comment

benjah Over a year ago

i tried but it's returns an syntax error:Uncaught SyntaxError: Unexpected token a

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