<?
if (!function_exists('YC_array_merge')) {
    function YC_array_merge($array1, $array2) {

        # Convert both to array if needed
        $a1_is_object = is_object($array1);
        $a2_is_object = is_object($array2);

        $a1 = (array) $array1;
        $a2 = (array) $array2;

        foreach ($a2 as $key => $value) {
            if (isset($a1[$key])) {
                if (is_array($a1[$key]) && is_array($value)) {
                    $a1[$key] = YC_array_merge($a1[$key], $value);
                } elseif (is_object($a1[$key]) && is_object($value)) {
                    $a1[$key] = YC_array_merge($a1[$key], $value);
                } else {
                    $a1[$key] = $value;
                }
            } else {
                $a1[$key] = $value;
            }
        }

        # Return in original format of array1
        return $a1_is_object ? (object) $a1 : $a1;
    }
}
<?
add_action('wp_ajax_remove_first_login_meta', 'remove_first_login_meta');
add_action('wp_ajax_nopriv_remove_first_login_meta', 'remove_first_login_meta');

function remove_first_login_meta() {
    if (is_user_logged_in()) {
        global $current_user;
        delete_user_meta($current_user->ID, 'first_login_custom_user');
        wp_send_json_success(['message' => 'تم حذف first_login_custom_user']);
    } else {
        wp_send_json_error(['message' => 'لم يتم تسجيل الدخول']);
    }
}