Sort array of objects by single key with date value

You can use Array.sort.

Here's an example:

var arr = [{
    "updated_at": "2012-01-01T06:25:24Z",
    "foo": "bar"
  },
  {
    "updated_at": "2012-01-09T11:25:13Z",
    "foo": "bar"
  },
  {
    "updated_at": "2012-01-05T04:13:24Z",
    "foo": "bar"
  }
]

arr.sort(function(a, b) {
  var keyA = new Date(a.updated_at),
    keyB = new Date(b.updated_at);
  // Compare the 2 dates
  if (keyA < keyB) return -1;
  if (keyA > keyB) return 1;
  return 0;
});

console.log(arr);

I already answered a really similar question here: Simple function to sort an array of objects

For that question I created this little function that might do what you want:

function sortByKey(array, key) {
    return array.sort(function(a, b) {
        var x = a[key]; var y = b[key];
        return ((x < y) ? -1 : ((x > y) ? 1 : 0));
    });
}