当我尝试添加JSON数组时，它会删除以前的数组。 （PHP）

EDIT: I am trying to merge 2 arrays together, saying that i want to add a new array to the json data without removing the json data that is already in the value.

EXAMPLE: $chatjson = [] has some json data in it which will look like this:

$chatjson = [{"sender":"Testing","message":"Hi"}] 

and i want to keep that data when it adds another array so it will look like this

$chatjson = [{"sender":"Testing","message":"Hi"},{"sender":"Testing","message":"Message 2!"}]

Should support my question.

<?php 
  include '../filter.php';
  $chatjson = [];
  $sender = SecurePost($_POST["sender"]);
  $message = SecurePost($_POST["message"]);

  if ($sender || $message) {
      $chatarray = array('sender' => $sender, 'message' => $message);
      $decodejson = json_decode($chatjson, true);

      $merge = array_merge((array)$chatarray, (array)$decodejson);
      $chatjson = json_encode($merge);
      echo $chatjson;
  }
?>

You need to change your code little bit:-

<?php 
  include '../filter.php';
  $chatjson = Array(); // define array like this
  $sender = SecurePost($_POST["sender"]);
  $message = SecurePost($_POST["message"]);

  if ($sender || $message) {
      $chatarray[] = array('sender' => $sender, 'message' => $message); // assign values every time to a new index.
      $decodejson = json_decode($chatjson, true);

      $merge = array_merge((array)$chatarray, (array)$decodejson); // push the new data
      $chatjson = json_encode($merge);
      echo $chatjson;
  }
?>