Add ability to alter rows in xls export

Wondering what could be the impact on performance on huge dataset...

Could it be problematic or not?

@lubwn ChatGPT suggest a better approach, on a performance point of view. Would it still work for your use case?

Better Approach: Call the Hook Once

Instead of calling the hook on each row, call it once before the loop, and then apply the returned logic within the loop.

🔧 Step-by-step

Step 1: Let hook implementations return callables or config

In other modules:

function my_module_my_custom_hook_prepare() {
  return function ($row) {
    // Do something with $row
    // e.g. modify, collect stats, tag, etc.
  };
}

Step 2: Invoke the hook once and collect callables

$callbacks = \Drupal::moduleHandler()->invokeAll('my_custom_hook_prepare');

This will return an array of functions (closures or callables) from all modules implementing hook_my_custom_hook_prepare().

Step 3: Use those callables inside the loop

foreach ($view->result as $row) {
  foreach ($callbacks as $callback) {
    $callback($row);
  }
}

✅ Why This Is Better

🔄 Before

• For n rows and m modules, you have O(n × m) hook resolution calls.
• Even for rows where no logic is needed, you're still scanning all modules.

⚡ After

• Hook resolution (invokeAll()) happens only once.
• For n rows, you directly apply the relevant logic.
• Much easier to cache or optimize later.

This feature can now be tested in the new Excel Serialization Extras → sandbox module.

Actually, the Drupal hook cache is pretty performant, so not sure the ChatGPT optimisation suggestion is really necessary.