WordPress 4.5 introduced partial (or selective) refreshes to the customizer.
As documented in the announcement on make.wordpress.org/core, the syntax that we have to use would look like this:
function my_register_blogname_partials( WP_Customize_Manager $wp_customize ) {
// Abort if selective refresh is not available.
if ( ! isset( $wp_customize->selective_refresh ) ) {
return;
}
$wp_customize->selective_refresh->add_partial( 'header_site_title', [
'selector' => '.site-title a',
'settings' => [ 'blogname' ],
'render_callback' => function() {
return get_bloginfo( 'name', 'display' );
},
] );
$wp_customize->selective_refresh->add_partial( 'document_title', [
'selector' => 'head > title',
'settings' => [ 'blogname' ],
'render_callback' => 'wp_get_document_title',
] );
}
add_action( 'customize_register', 'my_register_blogname_partials' );Kirki simplifies that process and you can add the arguments for partial refreshes in your fields using the partial_refresh argument. The example from above when combined with a text field would become like this:
Kirki::add_field( 'my_config', [
'type' => 'text',
'settings' => 'my_setting',
'label' => esc_html__( 'Text Control', 'kirki' ),
'section' => 'my_section',
'default' => esc_html__( 'This is a default value', 'kirki' ),
'priority' => 10,
'partial_refresh' => [
'header_site_title' => [
'selector' => '.site-title a',
'render_callback' => function() {
return get_bloginfo( 'name', 'display' );
},
],
'document_title' => [
'selector' => 'head > title',
'render_callback' => 'wp_get_document_title',
],
],
] );