wordpress return post data on click

ajax.js

jQuery(document).ready(function($) {
  $('.post').on('click', function(){
    getPostInfo($(this).attr('data-postid'));
  });
});

function getPostInfo(id) {
  jQuery.ajax({
    url: ajaxurl,
    dataType: 'json',
    data: {
      action: 'postdata',
      data: id
    },
    type: 'GET',
    success: returnData
  });
}

function returnData(res) {
  console.log(res);
}

functions.php

<?php

add_action( 'wp_ajax_postdata', 'prefix_ajax_postdata' );
add_action( 'wp_ajax_nopriv_postdata', 'prefix_ajax_postdata' );

function prefix_ajax_postdata() {
  $postID = intval($_GET['data']);
  $postdata = get_post($postID);
  echo json_encode($postdata);
  die();
}

template.html

<script type="text/javascript">var ajaxurl = "<?php echo admin_url('admin-ajax.php'); ?>";</script>
<?php
$posts = get_posts();
foreach ($posts as $p) :
  echo '<article class="post" id="'.$p->post_name.'" data-postid="'.$p->ID.'">.$p->post_title.'</article>';
endforeach;
?>