Get all terms for a taxonomy assigned to a WordPress post, returning them as a comma-delimited string.

bsd_get_taxonomy_terms_as_string.php

/*
* Use Case: A taxonomy named "Specialty" assigned to a post has several terms. 
* The user needs to receive them back like this: "landlord representation, real estate, tenant representation".
*
* Call it like this: 
* $term_list = bsd_get_taxonomy_terms_as_string( 'bsd-specialty', 1035 );
* Where bsd-specialty is the taxonomy slug and 1035 is the post ID.
*/

public function bsd_get_taxonomy_terms_as_string( $taxonomy_name, $object_id ) {
  $tax_terms = null;

  $taxonomy_terms = wp_get_object_terms( $object_id, $taxonomy_name );

  if ( !$taxonomy_terms ) {
    return $tax_terms;
  }
  
  if ( isset( $taxonomy_terms->errors ) ) {
    return $tax_terms;
  }

  $i = 0;
  
  $array_count = count( $taxonomy_terms );
  
  while ( $i < $array_count ) {
    if ( !$taxonomy_terms[$i]->name ) {
      continue;
    }
    
    $tax_name = $taxonomy_terms[$i]->name;
  
    if ( $i > 0 ) {
      $tax_terms = $tax_terms . ', ';
    }
  
    $tax_terms = $tax_terms . $tax_name;
  
    $i++;
  }
  
  return $tax_terms;
}