Wordpress JSON generator

function.php

function jsonGenerator(){
  // Auto Generate Sitemaps after every new post
  add_action("publish_post", "create_jsonfiles");
  add_action("publish_page", "create_jsonfiles"); 
  function create_jsonfiles() {   
    $postsForJson = get_posts(array(
         'numberposts' => -1,     
         // 'orderby' => 'modified',     
         'post_type'  => array('post','page'),     
         'order'    => 'DESC'   ));     

    foreach($postsForJson as $post) {
    	// setup_postdata( $post );
    	$filename = get_the_title($post->ID);
         $postdate = explode(" ", $post->post_modified);         
         $data .= '{'."\n".       
         '"title":"'. get_the_title($post->ID) .'",'. "\n".      
         '"slug":"'. get_permalink($post->ID) .'",'. "\n".      
         '"content":"'. get_the_content($post->ID) .'",'. "\n".      
         '"pubdate":"'. $postdate[0] .'"'. 
         "\n"."}";
        $fp = fopen(ABSPATH . $filename.".json", 'w');
  		fwrite($fp, $data); fclose($fp);
     }
    } 
}
jsonGenerator();