Query by co-authors for Co-Authors Plus

co-authors-query.php

<?php

function query_by_co_authors() {

  $current_user = wp_get_current_user();

  // Your standard query
  $post_args = array(
    'post_type' => 'post',
    'posts_per_page' => 10,
  );
  
  /**
   * Co-Authors stores post authors in a hidden taxonomy
   * so we need to query against that if possible, if not we
   * just use the usual post_author field
   */
  if ( class_exists( 'coauthors_plus' ) ) {
  	global $coauthors_plus;
  
  	$author_term            = $coauthors_plus->get_author_term( $current_user );
  	$post_args['tax_query'] = array(
  		array(
  			'taxonomy' => $coauthors_plus->coauthor_taxonomy,
  			'field'    => 'name',
  			'terms'    => $author_term->name,
  		),
  	);
  } else {
  	$post_args['author'] = $current_user->ID;
  }
  
  return $post_args;
}