Wordpress Disable Comments (add to function.php)

class-comments.php

<?php
/**
 * Class Comments.
 * Code refactored from:
 * https://gist.github.com/mattclements/eab5ef656b2f946c4bfb
 *
 * @package Foo
 */

namespace Boop;

/**
 * Class Comments - actions and filters related to WordPress comments.
 *
 * @package Foo
 */
class Comments {


	/**
	 * Static function must be called after require within functions.php
	 * This will setup all action and filter hooks related to comments.
	 */
	public static function initialise() {

		$self = new self();

		// Admin actions.
		add_action( 'admin_init', array( $self, 'disable_comments_post_types_support' ) );
		add_action( 'admin_init', array( $self, 'disable_comments_dashboard' ) );
		add_action( 'admin_init', array( $self, 'disable_comments_admin_menu_redirect' ) );
		add_action( 'admin_menu', array( $self, 'disable_comments_admin_menu' ) );
		add_action( 'wp_before_admin_bar_render', array( $self, 'admin_bar_render' ) );

		// Frontend.
		add_action( 'init', array( $self, 'disable_comments_admin_bar' ) );

		// Close comments on the front-end.
		add_filter( 'comments_open', '__return_false', 20, 2 );
		add_filter( 'pings_open', '__return_false', 20, 2 );
		// Hide existing comments.
		add_filter( 'comments_array', '__return_empty_array', 10, 2 );

	}

	/** Disable support for comments and trackbacks in post types. */
	public function disable_comments_post_types_support() {
		$post_types = get_post_types();
		foreach ( $post_types as $post_type ) {
			if ( post_type_supports( $post_type, 'comments' ) ) {
				remove_post_type_support( $post_type, 'comments' );
				remove_post_type_support( $post_type, 'trackbacks' );
			}
		}
	}

	/** Remove comments page in menu. */
	public function disable_comments_admin_menu() {
		remove_menu_page( 'edit-comments.php' );
	}

	/** Redirect any user trying to access comments page. */
	public function disable_comments_admin_menu_redirect() {
		global $pagenow;
		if ( 'edit-comments.php' === $pagenow ) {
			wp_safe_redirect( admin_url() );
			exit;
		}
	}


	/** Remove comments metabox from dashboard. */
	public function disable_comments_dashboard() {
		remove_meta_box( 'dashboard_recent_comments', 'dashboard', 'normal' );
	}
	/**  Remove comments links from admin bar. */
	public function disable_comments_admin_bar() {
		if ( is_admin_bar_showing() ) {
			remove_action( 'admin_bar_menu', 'wp_admin_bar_comments_menu', 60 );
		}
	}

	/**  Remove comments links from admin bar. */
	public function admin_bar_render() {
		global $wp_admin_bar;
		$wp_admin_bar->remove_menu( 'comments' );
	}

}