Utility wordpress class to extend tiny MCE

tiny-mce.php

<?php

/**
 * Utility class to extend tiny mce
 */

class EchoTinyMCE {

    public function __construct() {
        
        // Enable style dropdown menu
        add_filter( 'mce_buttons', array( $this, 'enable_styleselect' ) );

        // Add new styles to the TinyMCE "formats" menu dropdown.
        add_filter( 'tiny_mce_before_init', array( $this, 'add_formats' ) );

        // Add TinyMCE editor stylesheet
        add_action( 'after_setup_theme',  array( $this, 'load_editor_stylsheet' ) );

        // Add TinyMCE javascript
        add_action( 'mce_external_plugins', array( $this, 'load_editor_script' ) );
        add_action( 'mce_buttons', array( $this, 'register_editor_script' ) );

        add_filter( 'tiny_mce_before_init', array( $this, 'add_editor_class') );
    }

    /**
     * Enable styleselect
     * @param Array $buttons array of enabled TinyMCE buttons
     * @return Array Updated array of enabled TinyMCE buttons
     */

    public function enable_styleselect( Array $buttons ) {
        array_push( $buttons, 'styleselect' );
        return $buttons;
    }

    /**
     * Add "formats" menu drowdown on TinyMCE.
     * This adds a theme button and highlight options
     * @param Array $settings array of TinyMCE settings
     */

    public function add_formats( Array $settings ) {
        
        $styles = array(
            array(
                "title" => "Buttons",
                "items" => array(
                    array(
                        "title"     => "Primary button",
                        "selector"  => 'a',
                        "classes"   => "button"
                    ),
                    array(
                        "title"     => "Secondary button",
                        "selector"  => 'a',
                        "classes"   => "button-alt"
                    )
                )
            ),
            array(
                "title" => "Lists",
                "items" => array(
                    array(
                        "title"     => "Two column",
                        "selector"  => 'ul',
                        "classes"   => "ul-two-col"
                    ),
                    array(
                        "title"     => "Large links",
                        "selector"  => 'ul',
                        "classes"   => "ul-large-links"
                    )
                )
            )

        );

        // Merge with existing settings
        $settings['style_formats_merge'] = true;
        $settings['style_formats'] = json_encode( $styles );
        
        return $settings;
    }


    public function load_editor_stylsheet() {

        add_editor_style( trailingslashit( get_template_directory_uri() ) . 'assets/css/reset.css?v=' . _S_VERSION );
        add_editor_style( trailingslashit( get_template_directory_uri() ) . 'assets/css/bootstrap.min.css?v=' . _S_VERSION );
        add_editor_style( trailingslashit( get_template_directory_uri() ) . 'assets/css/main.css?v=' . _S_VERSION );
        add_editor_style( trailingslashit( get_template_directory_uri() ) . 'assets/css/tiny-mce.css?v=' . _S_VERSION );
    
    }

    /**
     * Load additional plugin(s) for TinyMCE
     * @param Array $plugin_array array of available plugins
     * @return Array $plugin_array modified array of available plugins
     */

    public function load_editor_script( Array $plugin_array ) {
        $plugin_array['echo_mce_button'] = get_template_directory_uri() . '/assets/js/mce-button.js?v=10';
        return $plugin_array;
    }

    /**
     * Register additional button(s) for TinyMCE
     * @param Array $buttons array of registered buttons
     * @return Array $buttons modified array of registered buttons
     */

    public function register_editor_script( Array $buttons ) {
        array_push( $buttons, 'echo_mce_button' );
        return $buttons;
    }

    public function add_editor_class( $mce ) {
        if ( $post = get_post() ) {
            $mce['body_class'] .= ' wysiwyg';
        }
    
        $mce['body_class'] .= ' custom-class another-custom-class etc';
    
        return $mce;
    }
 
}

new EchoTinyMCE();