WordPress: Custom User Roles

class-user-roles.php

<?php
/**
 * Customize user roles.
 */

/**
 * Class User_Roles.
 */
class User_Roles {
  
	/**
	 * The cache key.
	 *
	 * @var string
	 */
	private $cache_key = 'user_roles_hash';

	/**
	 * An array of the user roles to add.
	 *
	 * @var array
	 */
	private $user_roles = [];
  
	/**
	 * Existing instance.
	 *
	 * @var array
	 */
	protected static $instance;
	
	/**
	 * Get class instance.
	 *
	 * @return object
	 */
	public static function instance() {
		if ( ! isset( static::$instance ) ) {
			static::$instance = new static();
			static::$instance->setup();
		}
		return static::$instance;
	}

	/**
	 * Setup the class.
	 */
	private function setup() {
		// Add custom user roles here.
  
		// Setup the user roles.
		$this->setup_user_roles();
	}

	/**
	 * Check if we need to add the user roles.
	 */
	private function setup_user_roles() {
		// Check if we have already added our roles.
		$current_hash = get_transient( $this->cache_key );

		// We have not setup the user roles yet or they changed.
		if (
			false === $current_hash
			|| $current_hash !== $this->get_roles_hash()
		) {
			$this->add_user_roles();

			// Save the current hash.
			set_transient( $this->cache_key, $this->get_roles_hash() );
		}
	}

	/**
	 * Add the user roles.
	 */
	private function add_user_roles() {
		foreach ( $this->user_roles as $role => $args ) {
			if ( get_role( $role ) ) {
				remove_role( $role );
			}

			add_role( $role, $args['display_name'], $args['caps'] );
		}
	}

	/**
	 * Get the roles hash.
	 *
	 * @return string The hash code from the current state of the user roles.
	 */
	private function get_roles_hash() {
		return md5( wp_json_encode( $this->user_roles ) );
	}
}

User_Roles::instance();