Add a custom taxonomy dropdown filter to the WordPress Media Library

collection-filter.js

(function(){
	/**
	 * Create a new MediaLibraryTaxonomyFilter we later will instantiate
	 */
	var MediaLibraryTaxonomyFilter = wp.media.view.AttachmentFilters.extend({
		id: 'media-attachment-taxonomy-filter',

		createFilters: function() {
			var filters = {};
			// Formats the 'terms' we've included via wp_localize_script()
			_.each( MediaLibraryTaxonomyFilterData.terms || {}, function( value, index ) {
				filters[ index ] = {
					text: value.name,
					props: {
						// Change this: key needs to be the WP_Query var for the taxonomy
						collection: value.slug,
					}
				};
			});
			filters.all = {
				// Change this: use whatever default label you'd like
				text:  'All collections',
				props: {
					// Change this: key needs to be the WP_Query var for the taxonomy
					collection: ''
				},
				priority: 10
			};
			this.filters = filters;
		}
	});
	/**
	 * Extend and override wp.media.view.AttachmentsBrowser to include our new filter
	 */
	var AttachmentsBrowser = wp.media.view.AttachmentsBrowser;
	wp.media.view.AttachmentsBrowser = wp.media.view.AttachmentsBrowser.extend({
		createToolbar: function() {
			// Make sure to load the original toolbar
			AttachmentsBrowser.prototype.createToolbar.call( this );
			this.toolbar.set( 'MediaLibraryTaxonomyFilter', new MediaLibraryTaxonomyFilter({
				controller: this.controller,
				model:      this.collection.props,
				priority: -75
			}).render() );
		}
	});
})()

enqueue.php

<?php

add_action( 'wp_enqueue_media', function() {
	wp_enqueue_script( 'media-library-taxonomy-filter', get_stylesheet_directory_uri() . '/assets/js/collection-filter.js', array( 'media-editor', 'media-views' ) );
	// Load 'terms' into a JavaScript variable that collection-filter.js has access to
	wp_localize_script( 'media-library-taxonomy-filter', 'MediaLibraryTaxonomyFilterData', array(
		'terms'     => get_terms( 'collection', array( 'hide_empty' => false ) ),
	) );
	// Overrides code styling to accommodate for a third dropdown filter
	add_action( 'admin_footer', function(){
		?>
		<style>
		.media-modal-content .media-frame select.attachment-filters {
			max-width: -webkit-calc(33% - 12px);
			max-width: calc(33% - 12px);
		}
		</style>
		<?php
	});
});

Unfortunately, my category slug has a dash in it (art-categories) and JavaScript does not like the naked dash.

So I have changed line 16 to:

						'art-categories': value.slug,

And line 25 to:

					'art-categories': ''

The end result is that the popup menu is properly displayed on the media library page, but selecting different entries from that menu result in no change in the displayed media items. Does enclosing the key in single quotes as I did break this technique? Maybe I've done something else wrong?

Hi, @danielbachhuber. Thanks for the plugin, and apologies for the level of my English. I have three questions:

First, I want to suggest a little improvement. For hierarchical taxonomies, the following could be implemented:

$array_terms = create_hierarchical_names ( 'stmpujante_txn', $array_terms, 0, 0 ); // Load 'terms' into a JavaScript variable that collection-filter.js has access to wp_localize_script( 'media-library-taxonomy-filter', 'MediaLibraryTaxonomyFilterData', array( 'terms' => $array_terms // 'terms' => get_terms( 'stmpujante_txn', array( 'hide_empty' => false ) ), ) );

and the recursive function:

`

function create_hierarchical_names ( $taxonomy, $array_terms, $parent, $level ) {

$children = get_terms( array( 
	'taxonomy' => $taxonomy, 
	'orderby' => 'name',
	'hide_empty' => 0,
	'parent' => $parent
) );

if ( count( $children ) != 0 ) {
	
	foreach ( $children as $term ) {
		
		// By every son founded, we make a register
		$array_terms[] = array(
		
			'name' 		=> str_repeat( '-', $level ) . ' ' . $term->name,
			'slug' 		=> $term->slug
			
		);
		$array_terms = create_hierarchical_names ( $taxonomy, $array_terms, $term->term_id, $level+1 );
		
	}
	
}

// Returns the same array with the new registers
return $array_terms;

}

`

Second, the filter appears in the grid view, but not in the list view. Could you get it to appear in both views?

Finally, I've taken your code to include it in a more powerful plugin I'm developing. I would like, to upload it to the repository, include your registration name at wordpress.org. It would be an honor for me. You can see the progress of my plugin in my repository and the explanations of its development in mi blog (sorry, in spanish).

Sincerely, thanks in advance, Sergio Toca Moreno.

Same problem with a custom taxonomy, displayed but doesn't filter my media..
After search, I found solution in my case : I have to set 'query_var' => true when I register my cutom taxonomy.
Great, it works !
Thanks a lot Daniel for this work.

When I select an option, the contents by category are not updated

`
var MediaLibraryTaxonomyFilter = wp.media.view.AttachmentFilters.extend({
id: 'media-attachment-taxonomy-filter',

	createFilters: function() {
		var filters = {};
		// Formats the 'terms' we've included via wp_localize_script()
		_.each( MediaLibraryTaxonomyFilterData.terms || {}, function( value, index ) {
			filters[ index ] = {
				text: value.name,
				props: {
					// Change this: key needs to be the WP_Query var for the taxonomy
					collection: 'category',
				}
			};
		});
		filters.all = {
			// Change this: use whatever default label you'd like
			text:  'Todas las categorías',
			props: {
				// Change this: key needs to be the WP_Query var for the taxonomy
				collection: 'category'
			},
			priority: 10
		};
		this.filters = filters;
	}
});

`

Just a note... I could not get it to work at all using value.slug on line 16. I had to change it to value.term_id. After that, worked perfectly.