Q:

Attempting to remove a json object from an array by targeting key value

Disclaimer: I'm somewhat new to PHP. I'm trying to remove single objects from a json array, but when I attempt to delete the DOM object rectangle (each of which represents an array object), then process.php ends up making a copy of the array and appending it to the original array. 
When I click the delete button (class rectangle-delete), I change the deleteStatus hidden input value to delete which I'm trying to pick up in process.php. This is the particular bit in process.php that I thought would do the trick:
 foreach($arr_data as $key => $value) {
        if($value->value != "delete") {
            $arr_data[] = $value;
        }
     }

Here is the entire process.php:
<?php

   //$myFile = "data/data.json";
   $filename = $_POST['store-template-name'];
   $myFile = "data/" . $filename;
   $arr_data = array(); // create empty array

  try
  {
       //Get form data
       $formdata = array(
          'ID'=> $_POST['ID'],
          'attributeName'=> $_POST['attributeName'],
          'deleteStatus'=> $_POST['deleteStatus'],
          'attributeType'=> $_POST['attributeType']
       );
       //Get data from existing json file
       $jsondata = file_get_contents($myFile);
       // converts json data into array
       $arr_data = json_decode($jsondata, true);
       $updateKey = null;
       foreach ($arr_data as $k => $v) {
            if ($v['ID'] == $formdata['ID']) {
                $updateKey = $k;
            }
        }
       //  delete object in json
       foreach($arr_data as $key => $value) {
          if($value->value != "delete") {
              $arr_data[] = $value;
          }
       }
        if ($updateKey === null) {
            array_push($arr_data,$formdata);
        } else {
            $arr_data[$updateKey] = $formdata;
        }

       $jsondata = json_encode($arr_data);

       //write json data into data.json file
       if(file_put_contents($myFile, $jsondata)) {
            echo 'Data successfully saved';
        }
       else
            echo "error";
   }
   catch (Exception $e) {
            echo 'Caught exception: ',  $e->getMessage(), "\n";
   }
?>

A:

Maybe you are trying to filter your $arr_data array to remove the entities when the value is "delete", Am I right? If yes, you could try this.
foreach($arr_data as $key => $value) {
   if($value->value != "delete") {
     $arr_data[] = $value;
   }else{
      unset($arr_data[$key]);
   }
}

or this
$arr_data = array_filter($arr_data, function($value){
     return $value->value != "delete";
});

