add-defer-async-in-js.php

<?php

/**
 * Add async and defer to javascript file only for Homepage
 */
function yasglobal_defer_javascripts( $url ) {
  if ( ! is_front_page() ) return $url; // check the the page is front or not.
  if ( strpos( $url, '.js' ) === false || strpos( $url, 'main.min.js' ) === false ) return $url; // Check file type and specific file. If the file type is something else rather than .js or if this a specified JS File then return the same URL Otherwise add async in it.
    return "$url' async='async";
}
add_filter( 'clean_url', 'yasglobal_defer_javascripts', 11, 1 );