Selective refresh example plugin

site-title-smilies.php

<?php
/**
 * Plugin name: Site Title (and Tagline) Smilies
 * Description: Demonstration of selective refresh in the Customizer. Selectors are targeting elements in Twenty Fifteen.
 * Author: Weston Ruter, XWP
 * Plugin URL: https://gist.github.com/westonruter/a15b99bdd07e6f4aae7a
 *
 * @package SiteTitleSmilies
 */

namespace SiteTitleSmilies;

/**
 * Convert smilies on blogname option.
 *
 * @param mixed  $data         The requested non-URL site information.
 * @param string $option_name  Type of information requested.
 * @return string Filtered data.
 */
function convert_smilies_in_blogname( $data, $option_name ) {
	if ( 'name' === $option_name || 'description' === $option_name ) {
		$data = convert_smilies( $data );
	}
	return $data;
}
add_filter( 'bloginfo', __NAMESPACE__ . '\convert_smilies_in_blogname', 10, 2 );

/**
 * Render the site title.
 *
 * This function can be used in the template directly instead of calling bloginfo(),
 * and in this why the duplication of logic can be avoided.
 * For more complex partials with markup, use get_template_part().
 *
 * This function is called after the associated Customizer setting has already
 * been previewed, so we can call it just as if we were in the template normally.
 *
 * @see \get_template_part()
 * @return string|void If any text string is returned, it will be used instead of any text echoed and captured via output buffering.
 */
function render_blogname_partial() {
	bloginfo( 'name' );
}

/**
 * Render the site tagline.
 *
 * This function can be used in the template directly instead of calling bloginfo(),
 * and in this why the duplication of logic can be avoided.
 * For more complex partials with markup, use get_template_part().
 *
 * This function is called after the associated Customizer setting has already
 * been previewed, so we can call it just as if we were in the template normally.
 *
 * @see \get_template_part()
 * @return string|void If any text string is returned, it will be used instead of any text echoed and captured via output buffering.
 */
function render_blogdescription_partial() {
	bloginfo( 'description' );
}

/**
 * Register selective refresh partial.
 *
 * @param \WP_Customize_Manager $wp_customize Manager.
 */
function register_selective_refresh_partial( \WP_Customize_Manager $wp_customize ) {
	if ( ! isset( $wp_customize->selective_refresh ) ) {
		return;
	}

	// Note that this would be changed to $wp_customize->add_partial() once the method is added to WP_Customize_Manager.
	$wp_customize->selective_refresh->add_partial( 'blogname', array(
		'selector' => '.site-title a, .site-title:not(:has(a))',
		'render_callback' => __NAMESPACE__ . '\render_blogname_partial',
		'container_inclusive' => false,
	) );
	$wp_customize->selective_refresh->add_partial( 'document_title', array(
		'selector' => 'head > title',
		'settings' => array( 'blogname' ),
		'render_callback' => 'wp_get_document_title',
		'container_inclusive' => false,
	) );

	// Note that this would be changed to $wp_customize->add_partial() once the method is added to WP_Customize_Manager.
	$wp_customize->selective_refresh->add_partial( 'blogdescription', array(
		'selector' => '.site-description',
		'render_callback' => __NAMESPACE__ . '\render_blogdescription_partial',
		'container_inclusive' => false,
	) );

	$setting = $wp_customize->get_setting( 'blogdescription' );
	$setting->transport = 'postMessage';
}
add_action( 'customize_register', __NAMESPACE__ . '\register_selective_refresh_partial', 100 );