Register custom style formats to TinyMCE in WordPress

custom-tinymce-0.php

<?php

/**
 * custom_tinymce
 */
function vpm_custom_tinymce( $settings ) {

	// Define our custom formats
	$style_formats = array(
		array(
			// Your style format here
		),
		array(
			// Your 2nd style format here
		),
    	);
    	

	// We need the style formats in JSON format
	$settings['style_formats'] = json_encode( $style_formats );

	// Return the $settings variable,
	// now with our custom formats
	return $settings;

}

add_filter( 'tiny_mce_before_init', 'vpm_custom_tinymce' );

custom-tinymce-1.php

<?php

// Replace lines 8–16 in the previous file with the block below:

$style_formats = array(
    array(
        'title'   => 'Pull Quote',
        'block'   => 'aside',
        'classes' => 'pull-quote',
        'wrapper' => true,
        'styles'  => array(
            'float'      => 'right',
            'width'      => '40%',
            'borderLeft' => '4px solid black',
            'margin'     => '0 0 0 20px',
            'padding'    => '0 0 0 15px',
            'fontStyle'  => 'italic'
        ),
    ),
);

custom-tinymce-2.php

<?php

// Arrays all the way down...

$style_formats = array(
    array(
        'title'   => 'Pull Quote',
        'block'   => 'aside',
        'classes' => 'pull-quote',
        'wrapper' => true,
        'styles'  => array(
            'float'      => 'right',
            'width'      => '40%',
            'borderLeft' => '4px solid black',
            'margin'     => '0 0 0 20px',
            'padding'    => '0 0 0 15px',
            'fontStyle'  => 'italic'
        ),
    ),
    array(
        'title'    => 'No Indent paragraph',
        'selector' => 'p',
        'classes'  => 'no-indent',
        'wrapper'  => true,
    ),
);