* Dependencies API: WP_Dependencies base class
* @subpackage Dependencies
* Core base class extended to register items.
* An array of registered handle objects.
public $registered = array();
* An array of handles of queued objects.
* An array of handles of objects to queue.
* An array of handles of objects already queued.
* An array of additional arguments passed when a handle is registered.
* Arguments are appended to the item query string.
* An array of handle groups to enqueue.
public $groups = array();
* A handle group to enqueue.
* Cached lookup array of flattened queued items and dependencies.
private $all_queued_deps;
* Processes the items and dependencies.
* Processes the items passed to it or the queue, and their dependencies.
* @since 2.8.0 Added the `$group` parameter.
* @param string|string[]|false $handles Optional. Items to be processed: queue (false),
* single item (string), or multiple items (array of strings).
* @param int|false $group Optional. Group level: level (int), no groups (false).
* @return string[] Array of handles of items that have been processed.
public function do_items( $handles = false, $group = false ) {
* If nothing is passed, print the queue. If a string is passed,
* print that item. If an array is passed, print those items.
$handles = false === $handles ? $this->queue : (array) $handles;
$this->all_deps( $handles );
foreach ( $this->to_do as $key => $handle ) {
if ( ! in_array( $handle, $this->done, true ) && isset( $this->registered[ $handle ] ) ) {
* Attempt to process the item. If successful,
* add the handle to the done array.
* Unset the item from the to_do array.
if ( $this->do_item( $handle, $group ) ) {
unset( $this->to_do[ $key ] );
* Processes a dependency.
* @since 5.5.0 Added the `$group` parameter.
* @param string $handle Name of the item. Should be unique.
* @param int|false $group Optional. Group level: level (int), no groups (false).
* @return bool True on success, false if not set.
public function do_item( $handle, $group = false ) {
return isset( $this->registered[ $handle ] );
* Determines dependencies.
* Recursively builds an array of items to process taking
* dependencies into account. Does NOT catch infinite loops.
* @since 2.6.0 Moved from `WP_Scripts`.
* @since 2.8.0 Added the `$group` parameter.
* @param string|string[] $handles Item handle (string) or item handles (array of strings).
* @param bool $recursion Optional. Internal flag that function is calling itself.
* @param int|false $group Optional. Group level: level (int), no groups (false).
* @return bool True on success, false on failure.
public function all_deps( $handles, $recursion = false, $group = false ) {
$handles = (array) $handles;
foreach ( $handles as $handle ) {
$handle_parts = explode( '?', $handle );
$handle = $handle_parts[0];
$queued = in_array( $handle, $this->to_do, true );
if ( in_array( $handle, $this->done, true ) ) { // Already done.
$moved = $this->set_group( $handle, $recursion, $group );
$new_group = $this->groups[ $handle ];
if ( $queued && ! $moved ) { // Already queued and in the right group.
if ( ! isset( $this->registered[ $handle ] ) ) {
$keep_going = false; // Item doesn't exist.
} elseif ( $this->registered[ $handle ]->deps && array_diff( $this->registered[ $handle ]->deps, array_keys( $this->registered ) ) ) {
$keep_going = false; // Item requires dependencies that don't exist.
} elseif ( $this->registered[ $handle ]->deps && ! $this->all_deps( $this->registered[ $handle ]->deps, true, $new_group ) ) {
$keep_going = false; // Item requires dependencies that don't exist.
if ( ! $keep_going ) { // Either item or its dependencies don't exist.
return false; // Abort this branch.
continue; // We're at the top level. Move on to the next one.
if ( $queued ) { // Already grabbed it and its dependencies.
if ( isset( $handle_parts[1] ) ) {
$this->args[ $handle ] = $handle_parts[1];
$this->to_do[] = $handle;
* Registers the item if no item of that name already exists.
* @since 2.6.0 Moved from `WP_Scripts`.
* @param string $handle Name of the item. Should be unique.
* @param string|bool $src Full URL of the item, or path of the item relative
* to the WordPress root directory. If source is set to false,
* item is an alias of other items it depends on.
* @param string[] $deps Optional. An array of registered item handles this item depends on.
* @param string|bool|null $ver Optional. String specifying item version number, if it has one,
* which is added to the URL as a query string for cache busting purposes.
* If version is set to false, a version number is automatically added
* equal to current installed WordPress version.
* If set to null, no version is added.
* @param mixed $args Optional. Custom property of the item. NOT the class property $args.
* Examples: $media, $in_footer.
* @return bool Whether the item has been registered. True on success, false on failure.
public function add( $handle, $src, $deps = array(), $ver = false, $args = null ) {
if ( isset( $this->registered[ $handle ] ) ) {
$this->registered[ $handle ] = new _WP_Dependency( $handle, $src, $deps, $ver, $args );
* Adds data to a registered item.
* @param string $handle Name of the item. Should be unique.
* @param string $key The data key.
* @param mixed $value The data value.
* @return bool True on success, false on failure.
public function add_data( $handle, $key, $value ) {
if ( ! isset( $this->registered[ $handle ] ) ) {
return $this->registered[ $handle ]->add_data( $key, $value );
* Gets data associated with a registered item.
* @param string $handle Name of the item. Should be unique.
* @param string $key The data key.
* @return mixed Extra item data (string), false otherwise.
public function get_data( $handle, $key ) {
if ( ! isset( $this->registered[ $handle ] ) ) {
if ( ! isset( $this->registered[ $handle ]->extra[ $key ] ) ) {
return $this->registered[ $handle ]->extra[ $key ];
* Un-register an item or items.
* @since 2.6.0 Moved from `WP_Scripts`.
* @param string|string[] $handles Item handle (string) or item handles (array of strings).
public function remove( $handles ) {
foreach ( (array) $handles as $handle ) {
unset( $this->registered[ $handle ] );
* Queue an item or items.
* Decodes handles and arguments, then queues handles and stores
* arguments in the class property $args. For example in extending
* classes, $args is appended to the item url as a query string.
* Note $args is NOT the $args property of items in the $registered array.
* @since 2.6.0 Moved from `WP_Scripts`.
* @param string|string[] $handles Item handle (string) or item handles (array of strings).
public function enqueue( $handles ) {
foreach ( (array) $handles as $handle ) {
$handle = explode( '?', $handle );
if ( ! in_array( $handle[0], $this->queue, true ) && isset( $this->registered[ $handle[0] ] ) ) {
$this->queue[] = $handle[0];
// Reset all dependencies so they must be recalculated in recurse_deps().
$this->all_queued_deps = null;
if ( isset( $handle[1] ) ) {
$this->args[ $handle[0] ] = $handle[1];
* Dequeue an item or items.
* Decodes handles and arguments, then dequeues handles
* and removes arguments from the class property $args.
* @since 2.6.0 Moved from `WP_Scripts`.
* @param string|string[] $handles Item handle (string) or item handles (array of strings).
public function dequeue( $handles ) {
foreach ( (array) $handles as $handle ) {
$handle = explode( '?', $handle );
$key = array_search( $handle[0], $this->queue, true );
// Reset all dependencies so they must be recalculated in recurse_deps().
$this->all_queued_deps = null;
unset( $this->queue[ $key ] );
unset( $this->args[ $handle[0] ] );
* Recursively search the passed dependency tree for $handle.
* @param string[] $queue An array of queued _WP_Dependency handles.
* @param string $handle Name of the item. Should be unique.
* @return bool Whether the handle is found after recursively searching the dependency tree.
protected function recurse_deps( $queue, $handle ) {
if ( isset( $this->all_queued_deps ) ) {
return isset( $this->all_queued_deps[ $handle ] );
$all_deps = array_fill_keys( $queue, true );
foreach ( $queue as $queued ) {
if ( ! isset( $done[ $queued ] ) && isset( $this->registered[ $queued ] ) ) {
$deps = $this->registered[ $queued ]->deps;
$all_deps += array_fill_keys( $deps, true );
array_push( $queues, $deps );
$queue = array_pop( $queues );
$this->all_queued_deps = $all_deps;
return isset( $this->all_queued_deps[ $handle ] );
* Query list for an item.
* @since 2.6.0 Moved from `WP_Scripts`.
* @param string $handle Name of the item. Should be unique.
* @param string $list Optional. Property name of list array. Default 'registered'.
* @return bool|_WP_Dependency Found, or object Item data.
public function query( $handle, $list = 'registered' ) {
case 'scripts': // Back compat.
if ( isset( $this->registered[ $handle ] ) ) {
return $this->registered[ $handle ];
if ( in_array( $handle, $this->queue, true ) ) {
return $this->recurse_deps( $this->queue, $handle );
case 'to_print': // Back compat.
return in_array( $handle, $this->to_do, true );
case 'printed': // Back compat.
return in_array( $handle, $this->done, true );
* Set item group, unless already in a lower group.
* @param string $handle Name of the item. Should be unique.
* @param bool $recursion Internal flag that calling function was called recursively.
* @param int|false $group Group level: level (int), no groups (false).
* @return bool Not already in the group or a lower group.
public function set_group( $handle, $recursion, $group ) {
if ( isset( $this->groups[ $handle ] ) && $this->groups[ $handle ] <= $group ) {
$this->groups[ $handle ] = $group;