The Ultimate Snippets to Boost WordPress Speed & Performance

<?php
/**
*Remove comment-reply.min.js from all pages except posts
*/
add_action( 'wp_enqueue_scripts', 'comment_reply_hook' );
function comment_reply_hook() {
if ( !is_single()) {
wp_deregister_script( 'comment-reply' );
}

<?php
/**
 * Disable the emoji's
 */
function disable_emojis() {
 remove_action( 'wp_head', 'print_emoji_detection_script', 7 );
 remove_action( 'admin_print_scripts', 'print_emoji_detection_script' );
 remove_action( 'wp_print_styles', 'print_emoji_styles' );
 remove_action( 'admin_print_styles', 'print_emoji_styles' );
 remove_filter( 'the_content_feed', 'wp_staticize_emoji' );
 remove_filter( 'comment_text_rss', 'wp_staticize_emoji' );
 remove_filter( 'wp_mail', 'wp_staticize_emoji_for_email' );
 add_filter( 'tiny_mce_plugins', 'disable_emojis_tinymce' );
 add_filter( 'wp_resource_hints', 'disable_emojis_remove_dns_prefetch', 10, 2 );
}
add_action( 'init', 'disable_emojis' );

/**
 * Filter function used to remove the tinymce emoji plugin.
 *
 * @param array $plugins
 * @return array Difference betwen the two arrays
 */
function disable_emojis_tinymce( $plugins ) {
 if ( is_array( $plugins ) ) {
 return array_diff( $plugins, array( 'wpemoji' ) );
 } else {
 return array();
 }
}

/**
 * Remove emoji CDN hostname from DNS prefetching hints.
 *
 * @param array $urls URLs to print for resource hints.
 * @param string $relation_type The relation type the URLs are printed for.
 * @return array Difference betwen the two arrays.
 */
function disable_emojis_remove_dns_prefetch( $urls, $relation_type ) {
 if ( 'dns-prefetch' == $relation_type ) {
 /** This filter is documented in wp-includes/formatting.php */
 $emoji_svg_url = apply_filters( 'emoji_svg_url', 'https://s.w.org/images/core/emoji/2/svg/' );

$urls = array_diff( $urls, array( $emoji_svg_url ) );
 }

return $urls;
}

function disable_embeds_code_init() {

 // Remove the REST API endpoint.
 remove_action( 'rest_api_init', 'wp_oembed_register_route' );

 // Turn off oEmbed auto discovery.
 add_filter( 'embed_oembed_discover', '__return_false' );

 // Don't filter oEmbed results.
 remove_filter( 'oembed_dataparse', 'wp_filter_oembed_result', 10 );

 // Remove oEmbed discovery links.
 remove_action( 'wp_head', 'wp_oembed_add_discovery_links' );

 // Remove oEmbed-specific JavaScript from the front-end and back-end.
 remove_action( 'wp_head', 'wp_oembed_add_host_js' );
 add_filter( 'tiny_mce_plugins', 'disable_embeds_tiny_mce_plugin' );

 // Remove all embeds rewrite rules.
 add_filter( 'rewrite_rules_array', 'disable_embeds_rewrites' );

 // Remove filter of the oEmbed result before any HTTP requests are made.
 remove_filter( 'pre_oembed_result', 'wp_filter_pre_oembed_result', 10 );
}

add_action( 'init', 'disable_embeds_code_init', 9999 );

function disable_embeds_tiny_mce_plugin($plugins) {
    return array_diff($plugins, array('wpembed'));
}

function disable_embeds_rewrites($rules) {
    foreach($rules as $rule => $rewrite) {
        if(false !== strpos($rewrite, 'embed=true')) {
            unset($rules[$rule]);
        }
    }
    return $rules;
}
function my_deregister_wp_embed(){
 wp_dequeue_script( 'wp-embed' );
}
add_action( 'wp_footer', 'my_deregister_wp_embed' );

function itsme_disable_feed() {
 wp_die( __( 'No feed available, please visit our <a href="'. esc_url( home_url( '/' ) ) .'">homepage</a>!' ) );
}

add_action('do_feed', 'itsme_disable_feed', 1);
add_action('do_feed_rdf', 'itsme_disable_feed', 1);
add_action('do_feed_rss', 'itsme_disable_feed', 1);
add_action('do_feed_rss2', 'itsme_disable_feed', 1);
add_action('do_feed_atom', 'itsme_disable_feed', 1);
add_action('do_feed_rss2_comments', 'itsme_disable_feed', 1);
add_action('do_feed_atom_comments', 'itsme_disable_feed', 1);
remove_action( 'wp_head', 'feed_links_extra', 3 );
remove_action( 'wp_head', 'feed_links', 2 );

<?php
//Remove jQuery migrate
function smartwp_remove_jquery_migrate( $scripts ) {
 if ( !is_admin() && !empty( $scripts->registered['jquery'] ) ) {
 $scripts->registered['jquery']->deps = array_diff( $scripts->registered['jquery']->deps, ['jquery-migrate'] );
 }
}
add_action('wp_default_scripts', 'smartwp_remove_jquery_migrate');

<?php
//Remove Query Strings From Static Resources
function arctica_remove_query_strings_from_static_resources( $src ) {
 if( strpos( $src, '?v=' ) ){
 $src = remove_query_arg( 'v', $src );
 }
 if( strpos( $src, '?ver=' ) ){
 $src = remove_query_arg( 'ver', $src );
 }
 return $src;
}
add_filter( 'script_loader_src', 'arctica_remove_query_strings_from_static_resources', 999 );
add_filter( 'style_loader_src', 'arctica_remove_query_strings_from_static_resources', 999 );