javascript - PHP array finding element error -

i've javascript file passes argument backend php file. try find out values true.

this passed parameter,

{"2":true,"3":false,"4":true} 

this php code extract keys of true arrays,

<?php   print_r(loop_filters($_request['filters']));  // functions starts here    function loop_filters($filters)   {     $filters = json_decode($filters);     // return $filters;     $filter_array = [];      while($filter_key = current($filters))     {       if($filter_key === true)       {         $filter_array[] = key($filters);       }       next($filters);     }     return $filter_array;   } ?> 

however output

array ( [0] => 2 ) 

why not detecting 4 true , give output like

array ( [0] => 2 , [1] => 4) 

what's wrong , how can fix it? thanks

your code doesn't work because of this:

while($filter_key = current($filters)) 

because in second iteration value be: false , know:

while(false) 

this won't run, end loop after first iteration already.

how solve it? remove next() calls , replace while loop foreach loop, e.g.

function loop_filters($filters) {     $filters = json_decode($filters);      foreach($filters $key => $filter_key) {         if($filter_key === true) {             $filter_array[] = $key;         }     }      return $filter_array; }