Parse JSON in JavaScript? [duplicate]

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This question already has an answer here:

I want to parse a JSON string in JavaScript. The response is something like

var response = '{"result":true,"count":1}';

How can I get the values result and count from this?

First answer

Most browsers support JSON.parse(), which is defined in ECMA-262 5th Edition (the specification that JavaScript is based on). Its usage is simple:

var json = '{"result":true,"count":1}',
    obj = JSON.parse(json);

alert(obj.count);

/* or ES6 */

const json = '{"result":true,"count":1}' || {};
const { result, count } = JSON.parse(json);
alert(result);
alert(count);

For the browsers that don’t you can implement it using json2.js.

As noted in the comments, if you’re already using jQuery, there is a $.parseJSON function that maps to JSON.parse if available or a form of eval in older browsers. However, this performs additional, unnecessary checks that are also performed by JSON.parse, so for the best all round performance I’d recommend using it like so:

var json = '{"result":true,"count":1}',
    obj = JSON && JSON.parse(json) || $.parseJSON(json);

This will ensure you use native JSON.parse immediately, rather than having jQuery perform sanity checks on the string before passing it to the native parsing function.

Second answer

If you are getting this from an outside site it might be helpful to use jQuery’s getJSON. If it’s a list you can iterate through it with $.each

$.getJSON(url, function (json) {
    alert(json.result);
    $.each(json.list, function (i, fb) {
        alert(fb.result);
    });
});

Third answer

If you want to use JSON 3 for older browsers, you can load it conditionally with:

<script>
    window.JSON || 
    document.write('<script src="//cdnjs.cloudflare.com/ajax/libs/json3/3.2.4/json3.min.js"><\/scr'+'ipt>');
</script>

Now the standard window.JSON object is available to you no matter what browser a client is running.

Reprint:https://stackoverflow.com/questions/4935632/parse-json-in-javascript
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