$.each doesn't respect the order of an array

Question

I'm trying to order a multidimensional array in PHP and then pass it to my javascript file to display it. I use the function $.map and $.each to display the data. The problem is that the JS reorder the array according to the id. eg if I have an array like this.

$array = array(1 => array('name' => 'A','last' => 'B'), 
               5 => array('name' => 'C','last' => 'D'),
               2 => array('name' => 'K','last' => 'Z'));

Javascript will sort it this way

    array = {1:{name:'A',last:'B'},2:{name:'C',last:'D'},5:{name:'K',last:'Z'}}

I'm using uasort to sort my array according to the name :

public function specialNameComparison($firstElmnt,$secondElmnt){
    if ($firstElmnt['name'] == $secondElmnt['name']) {
        return 0;
    }
    return ($firstElmnt['name'] < $secondElmnt['name']) ? -1 : 1;
}

uasort($users,array($this,'specialNameComparison'));
echo json_encode($users);
die();

And in javascript as I said i'am using $.each (I've tried $.map to) to simply display the data

$.each(json, function(key,value) {
   console.log(value.name);
 });

Why Javascript is doing this !?

You do not have an array. That is an object if it has { and } — epascarello, Jan 23 '19 at 14:48
To expand on what epscarello said, what you have is an _object_, not an _array_. There is no guarantee to the ordering of keys on an object. — Mike Cluck, Jan 23 '19 at 14:49
related: https://stackoverflow.com/questions/34955787/is-a-javascript-array-order-guaranteed — Rafael Herscovici, Jan 23 '19 at 14:49
PHP associative arrays become objects in javascript. Javascript does not have the concept of an associative array, natively. — Taplar, Jan 23 '19 at 14:50
Convert it to be a real array, and then order will be guaranteed. — Taplar, Jan 23 '19 at 14:59

score 3 · Accepted Answer · answered Jan 23 '19 at 15:04

As above commenters have pointed out you are creating an object not an array in JS there are no associative arrays and denoting your indices puts you into the context of an 'array like object'. if you need those keys I would advise something like:

$array = [
  [ 'key' => 1, 'name' => 'A','last' => 'B' ], 
  [ 'key' => 5, 'name' => 'C','last' => 'D' ],
  [ 'key' => 2, 'name' => 'K','last' => 'Z' ],
];

which when json encoded will output:

[
  { "key": 1, "name": "A","last": "B" }, 
  { "key": 5, "name": "C","last": "D" },
  { "key": 2, "name": "K","last": "Z" },
]

then your js can be:

const arr =  [
  { key: 1, name: 'A',last: 'B' }, 
  { key: 5, name: 'C',last: 'D' },
  { key: 2, name: 'K',last: 'Z' },
];

arr.forEach(({key, name, last }) => console.log(`key: ${key} - ${name} ${last}`))

$.each doesn't respect the order of an array

1 Answers1