$args_big = [
'type_post' => 'post',
];
if(!empty($_GET['post'])) {
$args_big['p'] = $_GET['post'];
}
$query = new WP_Query( $args_big );
if ( $query->have_posts() ) : while ( $query->have_posts() ) : $query->the_post();
$res[get_the_ID()] = [
'longText' => get_the_content(null, false),
];