Profile Builder User Listing with user posts

gistfile1.php

<?php 

//////////////////////////////////////////////////////////////////////////////////////////////////
// List user posts on the single user listing
//////////////////////////////////////////////////////////////////////////////////////////////////

add_shortcode( 'wppb-user-posts', 'wppb_custom_list_user_posts' );
function wppb_custom_list_user_posts(){
	//get user ID
	if (isset($_GET['userID'])){
		$user_id = $_GET['userID'];
	}else{
		$user_id = get_query_var( 'username' );
	}
	$output = '';
	
	if ( $user_id != '' ) {
		$args = array(
			'posts_per_page'   	=> -1,
			'author' 			=> $user_id,
		);
		$posts_array = get_posts( $args );
		
		if ( $posts_array != null ){
			ob_start();
			echo "<ul class='wppb-user-posts'>";
			foreach ( $posts_array as $post ){
				?>
				<li><a href="<?php echo get_permalink( $post->ID )?>"><?php echo $post->post_title; ?></a></li>
				<?php
				$output = ob_get_contents();
				ob_end_clean();	
			}
			echo "</ul>";
		} else { 
			ob_start();
			echo '<p><strong>No posts</strong></p>'; 
			$output = ob_get_contents();
			ob_end_clean();	
		}
	}
	
	return $output;
}