Get name of key in key/value pair in JSON using jQuery?

Question

Say I have this JSON:

[
    {
        \"ID\": \"1\",
        \"title\": \"Title 1\",
    },
    {
        \"ID\": \"2\",
        \"title\": \"Title 2\",
             


        

Answer 1

This can probably be made more efficient/concise, but the function below will do it.

var testJson = [ {'oi' : 1, 'arf': 2, 'foo' : 0}, {'oi': 5, 'arf': 7}];

function commonKeys(j)
{

    var fillUp = [];
    for(var i in j[0])
       fillUp.push(i);

    for(var i = 1; i < j.length; i++)
    {
       var cur = j[i]; var curArr = [];
       for (var i in cur) {curArr.push(i)};
       fillUp = fillUp.filter(function(x) {return (curArr.indexOf(x) != -1);});
    }

    return fillUp;
}

alert(commonKeys(testJson)); //oi,arf (not foo)