Question

73

How to parse JSON data when the property name is not known in advance?

rated 0 times [ 74] [ 1] / answers: 1 / hits: 18794 / 12 Years ago, thu, march 15, 2012, 12:00:00

Here is my response code in jQuery:

var response = $.parseJSON(response);



for (var i = 0; i < response.groupIds.length; i++) {

    console.log(response.groupIds[i], i);

}

Each response.groupIds[i] is of the form {unknown name:unknown value}.

I wish to access both of these bits of data in javascript, how do I accomplish this when I don't know in advance what e.g. unknown name is?

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isham

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answered 12 Years ago harleyterryp · Accepted Answer

Use Object.keys to retrieve a full list (array) of key names. A polyfill is available here.

var group = response.groupIds[i];



var allPropertyNames = Object.keys(group);

for (var j=0; j<allPropertyNames.length; j++) {

    var name = allPropertyNames[j];

    var value = group[name];

    // Do something

}

Your question's response format contains only one key-value pair. The code can then be reduced to:

var group = response.groupIds[i];

var name = Object.keys(group)[0]; // Get the first item of the list;  = key name

var value = group[name];

If you're not interested in the list, use a for-i-in loop with hasOwnProperty. The last method has to be used, to exclude properties which are inherit from the prototype.

for (var name in group) {

    if (group.hasOwnProperty(name)) {

        var value = group[name];

        // Do something

    }

}