Question

First this is not a duplicate questions. I’ve looked through some similar problem and most of the answer is what I am using right now.

Here is the problem set up,
on PHP side

$array = array('name' => 'a', 'data' => array('0'=>15,'0.25'=>'18','0.35'=>19,'1' =>20));
echo json_encode($array);

on the JS side

data = $.parseJSON(data); // data is the return from the php script
above

As you can see the $array[‘data’] is an associative array with numeric number as its key and sorted in order. While parsing into JSON, javascript altered the order of that array and sorted 0 and 1 as numeric key and put them to the head of the object.

I know this is standard behavior for certain browser such as chrome, and IE9.
I’ve read somewhere that people suggest stick with array strictly if I want to maintain the order of the array.
But my question is how do you feed back an array from PHP to javascript as an array instead of using json object? Or is there other solution to this kind of problem . Thanks for the input in advance.

Thanks for the input in advance

Answer 1

Use an array to maintain order, and then an object to create the map. There are two ways. I would suggest:

$array = array('name' => 'a', 'data' => 
  array(
    array('key' => 0, 'value' => 15),
    array('key' => 0.25, 'value' => 18),
    array('key' => 0.35, 'value' => 19),
    array('key' => 1, 'value' => 20),
  )
);
echo json_encode($array);

Which will give you the JSON:

{
    "name": "a",
    "data": [
       {"key": 0, "value": 15},
       {"key": 0.25, "value": 18},
       {"key": 0.35, "value": 19},
       {"key": 1, "value": 20}
    ]
}

Then you will have order but to look up a certain key will be more difficult. If you want that to be easy you can return a mapping object as well like this:

$array = array('name' => 'a', 'data' => 
  array(
    "0" => 15,
    "0.25" => 18,
    "0.35" => 19,
    "1" => 20,
  ),
  'order' => array("0", "0.25", "0.35", "1")
);
echo json_encode($array);

Which will give you:

{
    "name": "a",
    "data": {
       "0": 15,
       "0.25": 18,
       "0.35": 19,
       "1": 20
    },
    "order": ["0", "0.25", "0.35", "1"]
}

One of these two methods of returning your data should prove to be the most useful for your specific use case.