How to test if a string is JSON or not?

0 votes

I have a simple AJAX call, and the server will return either a JSON string with useful data or an error message string produced by the PHP function mysql_error(). How can I test whether this data is a JSON string or the error message.

It would be nice to use a function called isJSON just like you can use the function instanceof to test if something is an Array.

This is what I want:

if (isJSON(data)){
    //do some data stuff
}else{
    //report the error
    alert(data);
}
Oct 8 in Java-Script by kartik
• 35,820 points
60 views

1 answer to this question.

0 votes

Hello @kartik,

Use JSON.parse

function isJson(str) {
    try {
        JSON.parse(str);
    } catch (e) {
        return false;
    }
    return true;
}

Hope it helps!!
Thank you!!

answered Oct 8 by anonymous
• 78,120 points

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