Use aria-label to ensure Posts and Comments navigation has proper context in WordPress 5.3

Many themes (including bundled themes) use previous/next navigation in single post and pagination links in the posts/comments archives.

The markup output is under the responsibility of core private function _navigation_markup, which prints out an unlabelled <nav> element:

<nav class="navigation post-navigation" role="navigation">

This <nav> element defines an ARIA landmark by default: landmarks help assistive technology users to perceive the page main sections and jump through them. However, when a landmark is used more than once in a page, it needs to be distinguished from the other ones to let users understand what the landmark is about.

For reference, see ARIA Landmarks Example on W3.org.

To distinguish each context WordPress 5.3 will programmatically add specific aria-label parameter for each navigation menu. That parameter is being added to navigation menus generated by the following functions:

  • _navigation_markup()
  • get_the_post_navigation()
  • get_the_posts_navigation()
  • get_the_posts_pagination()
  • get_the_comments_navigation()
  • get_the_comments_pagination()

The following functions are also impacted as they are used to echo the result of the functions listed above:

  • the_post_navigation()
  • the_posts_navigation()
  • the_posts_pagination()
  • the_comments_navigation()
  • the_comments_pagination()

All these functions now implement aria_label parameter which can be used to pass custom value for the related HTML attribute.

For example:

the_post_navigation( array(
    'prev_text'          => __( 'previous: %title', 'text-domain' ),
    'next_text'          => __( 'next: %title', 'text-domain' ),
    'taxonomy'           => 'chapters',
    'aria_label'         => __( 'Chapters', 'text-domain' ),
) );

For reference, see the related Trac ticket: #47123

#5-3, #accessibility, #dev-notes