Add NextPage and Other Buttons to TinyMCE

Add TinyMCE Buttons

//Add NextPage and Other Buttons to TinyMCE
add_filter('mce_buttons', function ($mce_buttons) {
    $pos = array_search('wp_more', $mce_buttons, true);
    if ($pos !== false) {
        $buttons = array_slice($mce_buttons, 0, $pos + 1);
 
        $buttons[] = 'wp_page';
        $buttons[] = 'hr';      
 
        $mce_buttons = array_merge($buttons, array_slice($mce_buttons, $pos + 1));
    }
    return $mce_buttons;
});