JSON Object validation in JavaScript

Question

I am using JSON object as an input in the textfield. Is there any way to validate this JSON object in JavaScript??

Are you trying to validate that it's syntactically valid JSON or that it conforms to a certain schema? — jabclab, Dec 08 '11 at 13:13
I am just trying to check whether the object entered in textfield is valid JSON. — user1059229, Dec 08 '11 at 13:17
you can use intval function for example $id=intval($id); echo json_encode($data) — rashidkaif1, Dec 26 '12 at 12:54

score 28 · Accepted Answer · answered Dec 08 '11 at 13:32

28

Building on the idea of @Quentin, you can just do something like:

function isValidJson(json) {
    try {
        JSON.parse(json);
        return true;
    } catch (e) {
        return false;
    }
}

console.log(isValidJson("{}")); // true
console.log(isValidJson("abc")); // false

This will require json2.js to be deployed in the page in order to ensure cross-browser support for the JSON Object.

answered Dec 08 '11 at 13:32

jabclab

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Thanks for replying. But I am getting an error for valid JSON object also. – user1059229 Dec 08 '11 at 13:51
{ "id":"b9c8e5f2-50ae-102c-8da0-dv8gb9f250ae", "at":2, "tmax":100, "imp": [ { "impid":"dv8gb9f2-50ae-102c-8da0-12313a002cd2", "h":50, "w":320, "instl":0 } ], "app": { "aid":"73737", "name":"We Rule", "ver":"2.1.3" }, "device": { "dpid":"dfe9f2bdfe9f2bdfe9f2bdfe9f2bdfe9f2bdfe9f2b", "ip":"124.32.53.1", "ua":"Mozilla%2F5.0%20(iPhone%3B%20U%3B%20CPU%20iPhone" } } – user1059229 Dec 09 '11 at 11:53
It appears to work for me, have a look at this [jsFiddle](http://jsfiddle.net/F2ufR/). – jabclab Dec 09 '11 at 11:58
I am using this function on "onsubmit". Should this be a problem?? – user1059229 Dec 12 '11 at 10:19
Shouldn't be. Is it possible to set up a [jsFiddle](http://jsfiddle.net/) to demonstrate the scenario in which the code is failing? – jabclab Dec 12 '11 at 10:24
It worked. I was not passing correct value to the function.Thank u for ur help. – user1059229 Dec 13 '11 at 10:19
Its giving me an error for the same JSON string in IE compatibility view. – user1059229 Dec 19 '11 at 11:45
Have you got [json2.js](https://github.com/douglascrockford/JSON-js/blob/master/json2.js) included in your page? – jabclab Dec 21 '11 at 08:45
It doesn't work when you put numbers as an input. For example: console.log(isValidJson("123")); // true I think we need also check if input is a number. – user3816621 Sep 01 '20 at 12:31
@user3816621 A number string is a valid JSON string. – Heretic Monkey Sep 01 '20 at 12:51

score 3 · Answer 2 · answered Jan 25 '13 at 00:04

3

if you wish to validate the object to a certain schema, you could try JSD Validator

answered Jan 25 '13 at 00:04

Mark Homans

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score 0 · Answer 3 · answered Jun 12 '20 at 17:49

Here is the code that worked for me,

$scope.jsonFunc = function(json){
        try {
            $scope.jsonData = JSON.stringify(JSON.parse(json), null, 2);
            return true;
            $scope.errorMessage = "Valid JSON";
        } catch (e) {
            $scope.errorMessage = e.message;
            return false;
        }
}

score 0 · Answer 4 · answered Dec 08 '11 at 13:05

0

Run it through a JSON parser (json2.js if you aren't using a library with one built in) and see if you get data back.

answered Dec 08 '11 at 13:05

Quentin

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score 0 · Answer 5 · answered Dec 08 '11 at 13:19

Yes, there are quite a few JSON libraries available for your use.

Try these out when using Java:

Jackson - A High performance JSON processors
google-gson - Java library by google

Or if you prefer simple JavaScript, you can go with

David Walsh has given a full example of how to do this in javascript using Mootools, JSON Schema, in the following blog http://davidwalsh.name/json-validation. Give it a go.

JSON Object validation in JavaScript

5 Answers5

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