Closure in JavaScript vs PHP

I am trying to implement a very simple closure related task in PHP which is not going well. I have this solution in JavaScript. How do i implement this in PHP?

const data = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]

const getChunksOfTwo = () => {
  let pos = 0
  
  return () => {
     const start = pos
     const finish = start + 2
     const chunk = data.slice(start, finish)
     pos++
     return chunk
  }
}

// To initiate the closure
const closureFun = getChunksOfTwo()

// Call the closureFun
closureFun() // Gives [1, 2]
closureFun() // Gives [2, 3]
closureFun() // Gives [3, 4]

But in PHP the same apparently does not work. I am trying this:

$data = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20];

function getChunksOfTwo($data) {
   $pos = 0;

   return function() {
     $start = $pos;
     $finish = $start + 2;
     $chunk = array_slice($data, $start, $finish);
     $pos++;
     return $chunk;
   };
};

// To initiate the closure
$closureFun = getChunksOfTwo($data);

// Call the closureFun
$closureFun(); // Does not give [1, 2]
$closureFun(); // Does not give [2, 3]

>Solution :

You can try this

$data = [1,2, 3, 4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20];

function getChunksOfTwo($data) {
   $chunks = array_chunk($data, 2);
   $pos = 0;
   
   return function() use(&$pos, $data, $chunks) {
     return $chunks[$pos++];
   };
};

// To initiate the closure
$closureFun = getChunksOfTwo($data);

// Call the closureFun
print_r($closureFun()); // Does not give [1, 2]
print_r($closureFun()); // Does not give [2, 3]

& with var means passing by reference source

It has to be passed by reference to mutate that variable otherwise it copies the original and every new call will have the same value.

Outupt

Array
(
    [0] => 1
    [1] => 2
)
Array
(
    [0] => 3
    [1] => 4
)