how to close if fuction of that code without error?

Question

this code i created it to add meta keywords tag for only posts header with execluding for all website pages ( home & about & contact & blog & ...etc ) i add this code to function.php and each time i got error that i have to close if function with endif and each time i tried that i got error.. so please help

add_action('wp_head', function (){
  ?>
  <?php 
    if ( is_single() ) {
    echo get_post_meta( get_the_ID(), 'meta-head', true );  
  $postTags = get_the_tags();
  $tagNames = array();
  foreach($postTags as $tag) {
    $tagNames[] = $tag->name;          
      }
?>
<meta name="keywords" content="<?php echo implode($tagNames,","); ?>" />
  <?php
    }

Answer 1

You forgot to close the function

add_action('wp_head', function (){
  if ( is_single() ) { 
    echo get_post_meta( get_the_ID(), 'meta-head', true ); 
    $postTags = get_the_tags(); 
    $tagNames = array(); 
    foreach($postTags as $tag) { 
      $tagNames[] = $tag->name; 
     } 
     ?> 
     <meta name="keywords" content="<?php echo implode($tagNames,","); ?>" /> 
  <?php 
  }
 } // This one here