JSON object to Javascript Array

Question

I want to know what is the fastest function that can be used to convert a json object into a java script array here an example

var j = '[{"var1":"val1", "var2":"val2"}]';

var arr  ===> [var1] = "val1"

The bottom line is to avoid for loops as much as possible

For future reference: In JavaScript there is no associative array. So using `someObject[key]=value;` the someObject be any Object `{}`. It can be an Array since Array is an Object and can have other properties assigned to it with `someArray[key]=value` but there is no need for it to be an Array. What you wanted to do is have Object A.key take the values of Object B.key where B is the first element in an array created with JSSON.parse You could do this with `var configObj={};...obj=JSON.parse(config)[0];for (var k in obj){ configObj[k]=obj[k];}` — HMR, Nov 10 '13 at 04:49

plalx · Accepted Answer · 2013-11-09T21:15:46.757

3

Most modern browsers will support the native JSON.parse function.

var arr = JSON.parse('[{"var1":"val1", "var2":"val2"}]');

console.log(arr);

//Just to be clear for OP
console.log(Array.isArray(arr)); //true

I want the output to be Arr[var1] = "val1"] not [Object]

That means you want to object at index 0 in the array.

var obj = JSON.parse('[{"var1":"val1", "var2":"val2"}]')[0];

console.log(obj['var1']); //val1

If you only want the values:

var values = JSON.parse('[{"var1":"val1", "var2":"val2"}]').reduce(function (values, obj) {
    for (var k in obj) values.push(obj[k]);
    return values;
}, []);

console.log(values); //["val1", "val2"]

edited Nov 09 '13 at 21:15

answered Nov 09 '13 at 20:57

plalx

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Yes, every browser since IE8 knows `JSON.parse`: http://caniuse.com/json – Kijewski Nov 09 '13 at 21:01
I think the return of JSON.parse is Object not array, I want the return to be array type not Object – Mohammad Abu Musa Nov 09 '13 at 21:03
An Array is an Object in JavaScript. So the answer will work just fine. – Kijewski Nov 09 '13 at 21:05
That's because your input object is an array with a single item (ie object) in it. – Jondlm Nov 09 '13 at 21:06
I want the output to be Arr[var1] = "val1"] not [Object] var1: "val1" – Mohammad Abu Musa Nov 09 '13 at 21:07
@MohammadAbuMusa The return value is an `Array`, however `typeof arr` will be `object` if that's what you are looking at. – plalx Nov 09 '13 at 21:08
@MohammadAbuMusa I.e. you **don't** want the array but the contained object?? `var arr = JSON.parse(…)[0]`. – Kijewski Nov 09 '13 at 21:09
@kay exactly I want the contents of the object to merged into the array – Mohammad Abu Musa Nov 09 '13 at 21:11
@MohammadAbuMusa Have a look at the updated answer. – plalx Nov 09 '13 at 21:16
@MohammadAbuMusa you want the result to be an array (as in `arr.__proto__ === Array`), but it should have the keys of `arr[0]` to be merged into `arr`? – Kijewski Nov 09 '13 at 21:16
@plalx I think your solution can work, but it takes only values neglecting the keys. when I applied the code you provided it just neglected var1 as the key. I need both the key and the value I am trying to access them both. I have some trials to do – Mohammad Abu Musa Nov 09 '13 at 21:27
it just worked, thanks a lot I got now the key and the value and merged them into another array perfectly. do you have tips about its performance. I am still searching about some of the functions you used – Mohammad Abu Musa Nov 09 '13 at 21:34
This is the case I have been working on, I wanted to make TinyMCE works as EmberJS component so when I pass configurations through JSON TinyMCE is shown correctly. You can see a working example on http://jsbin.com/aRiPUkE/1/ – Mohammad Abu Musa Nov 09 '13 at 21:39

score 0 · Answer 2 · answered Nov 09 '13 at 20:57

0

If I understand you correctly, you can use JSON.parse.

var json = '[{"var1": "val1", "var2": "val2"}]';
var arr = JSON.parse(json);

answered Nov 09 '13 at 20:57

Mike Cluck

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score 0 · Answer 3 · answered Nov 09 '13 at 21:00

0

I usually use jQuery, though that might no longer be preferred.

var j = '[{"var1":"val1", "var2":"val2"}]';
var arr = jQuery.parseJSON( j );

This should work well in some older browsers if you need that kind of thing of course.

answered Nov 09 '13 at 21:00

Rohit Gupta

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JSON object to Javascript Array

3 Answers3