diff -r 7b1b88e27a20 -r 48c4eec2b7e6 wp/wp-includes/class-wp-scripts.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-includes/class-wp-scripts.php	Fri Sep 05 18:40:08 2025 +0200
@@ -0,0 +1,1013 @@
+<?php
+/**
+ * Dependencies API: WP_Scripts class
+ *
+ * @since 2.6.0
+ *
+ * @package WordPress
+ * @subpackage Dependencies
+ */
+
+/**
+ * Core class used to register scripts.
+ *
+ * @since 2.1.0
+ *
+ * @see WP_Dependencies
+ */
+class WP_Scripts extends WP_Dependencies {
+	/**
+	 * Base URL for scripts.
+	 *
+	 * Full URL with trailing slash.
+	 *
+	 * @since 2.6.0
+	 * @var string
+	 */
+	public $base_url;
+
+	/**
+	 * URL of the content directory.
+	 *
+	 * @since 2.8.0
+	 * @var string
+	 */
+	public $content_url;
+
+	/**
+	 * Default version string for scripts.
+	 *
+	 * @since 2.6.0
+	 * @var string
+	 */
+	public $default_version;
+
+	/**
+	 * Holds handles of scripts which are enqueued in footer.
+	 *
+	 * @since 2.8.0
+	 * @var array
+	 */
+	public $in_footer = array();
+
+	/**
+	 * Holds a list of script handles which will be concatenated.
+	 *
+	 * @since 2.8.0
+	 * @var string
+	 */
+	public $concat = '';
+
+	/**
+	 * Holds a string which contains script handles and their version.
+	 *
+	 * @since 2.8.0
+	 * @deprecated 3.4.0
+	 * @var string
+	 */
+	public $concat_version = '';
+
+	/**
+	 * Whether to perform concatenation.
+	 *
+	 * @since 2.8.0
+	 * @var bool
+	 */
+	public $do_concat = false;
+
+	/**
+	 * Holds HTML markup of scripts and additional data if concatenation
+	 * is enabled.
+	 *
+	 * @since 2.8.0
+	 * @var string
+	 */
+	public $print_html = '';
+
+	/**
+	 * Holds inline code if concatenation is enabled.
+	 *
+	 * @since 2.8.0
+	 * @var string
+	 */
+	public $print_code = '';
+
+	/**
+	 * Holds a list of script handles which are not in the default directory
+	 * if concatenation is enabled.
+	 *
+	 * Unused in core.
+	 *
+	 * @since 2.8.0
+	 * @var string
+	 */
+	public $ext_handles = '';
+
+	/**
+	 * Holds a string which contains handles and versions of scripts which
+	 * are not in the default directory if concatenation is enabled.
+	 *
+	 * Unused in core.
+	 *
+	 * @since 2.8.0
+	 * @var string
+	 */
+	public $ext_version = '';
+
+	/**
+	 * List of default directories.
+	 *
+	 * @since 2.8.0
+	 * @var array
+	 */
+	public $default_dirs;
+
+	/**
+	 * Holds a mapping of dependents (as handles) for a given script handle.
+	 * Used to optimize recursive dependency tree checks.
+	 *
+	 * @since 6.3.0
+	 * @var array
+	 */
+	private $dependents_map = array();
+
+	/**
+	 * Holds a reference to the delayed (non-blocking) script loading strategies.
+	 * Used by methods that validate loading strategies.
+	 *
+	 * @since 6.3.0
+	 * @var string[]
+	 */
+	private $delayed_strategies = array( 'defer', 'async' );
+
+	/**
+	 * Constructor.
+	 *
+	 * @since 2.6.0
+	 */
+	public function __construct() {
+		$this->init();
+		add_action( 'init', array( $this, 'init' ), 0 );
+	}
+
+	/**
+	 * Initialize the class.
+	 *
+	 * @since 3.4.0
+	 */
+	public function init() {
+		/**
+		 * Fires when the WP_Scripts instance is initialized.
+		 *
+		 * @since 2.6.0
+		 *
+		 * @param WP_Scripts $wp_scripts WP_Scripts instance (passed by reference).
+		 */
+		do_action_ref_array( 'wp_default_scripts', array( &$this ) );
+	}
+
+	/**
+	 * Prints scripts.
+	 *
+	 * Prints the scripts passed to it or the print queue. Also prints all necessary dependencies.
+	 *
+	 * @since 2.1.0
+	 * @since 2.8.0 Added the `$group` parameter.
+	 *
+	 * @param string|string[]|false $handles Optional. Scripts to be printed: queue (false),
+	 *                                       single script (string), or multiple scripts (array of strings).
+	 *                                       Default false.
+	 * @param int|false             $group   Optional. Group level: level (int), no groups (false).
+	 *                                       Default false.
+	 * @return string[] Handles of scripts that have been printed.
+	 */
+	public function print_scripts( $handles = false, $group = false ) {
+		return $this->do_items( $handles, $group );
+	}
+
+	/**
+	 * Prints extra scripts of a registered script.
+	 *
+	 * @since 2.1.0
+	 * @since 2.8.0 Added the `$display` parameter.
+	 * @deprecated 3.3.0
+	 *
+	 * @see print_extra_script()
+	 *
+	 * @param string $handle  The script's registered handle.
+	 * @param bool   $display Optional. Whether to print the extra script
+	 *                        instead of just returning it. Default true.
+	 * @return bool|string|void Void if no data exists, extra scripts if `$display` is true,
+	 *                          true otherwise.
+	 */
+	public function print_scripts_l10n( $handle, $display = true ) {
+		_deprecated_function( __FUNCTION__, '3.3.0', 'WP_Scripts::print_extra_script()' );
+		return $this->print_extra_script( $handle, $display );
+	}
+
+	/**
+	 * Prints extra scripts of a registered script.
+	 *
+	 * @since 3.3.0
+	 *
+	 * @param string $handle  The script's registered handle.
+	 * @param bool   $display Optional. Whether to print the extra script
+	 *                        instead of just returning it. Default true.
+	 * @return bool|string|void Void if no data exists, extra scripts if `$display` is true,
+	 *                          true otherwise.
+	 */
+	public function print_extra_script( $handle, $display = true ) {
+		$output = $this->get_data( $handle, 'data' );
+		if ( ! $output ) {
+			return;
+		}
+
+		if ( ! $display ) {
+			return $output;
+		}
+
+		wp_print_inline_script_tag( $output, array( 'id' => "{$handle}-js-extra" ) );
+
+		return true;
+	}
+
+	/**
+	 * Checks whether all dependents of a given handle are in the footer.
+	 *
+	 * If there are no dependents, this is considered the same as if all dependents were in the footer.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @param string $handle Script handle.
+	 * @return bool Whether all dependents are in the footer.
+	 */
+	private function are_all_dependents_in_footer( $handle ) {
+		foreach ( $this->get_dependents( $handle ) as $dep ) {
+			if ( isset( $this->groups[ $dep ] ) && 0 === $this->groups[ $dep ] ) {
+				return false;
+			}
+		}
+		return true;
+	}
+
+	/**
+	 * Processes a script dependency.
+	 *
+	 * @since 2.6.0
+	 * @since 2.8.0 Added the `$group` parameter.
+	 *
+	 * @see WP_Dependencies::do_item()
+	 *
+	 * @param string    $handle The script's registered handle.
+	 * @param int|false $group  Optional. Group level: level (int), no groups (false).
+	 *                          Default false.
+	 * @return bool True on success, false on failure.
+	 */
+	public function do_item( $handle, $group = false ) {
+		if ( ! parent::do_item( $handle ) ) {
+			return false;
+		}
+
+		if ( 0 === $group && $this->groups[ $handle ] > 0 ) {
+			$this->in_footer[] = $handle;
+			return false;
+		}
+
+		if ( false === $group && in_array( $handle, $this->in_footer, true ) ) {
+			$this->in_footer = array_diff( $this->in_footer, (array) $handle );
+		}
+
+		$obj = $this->registered[ $handle ];
+
+		if ( null === $obj->ver ) {
+			$ver = '';
+		} else {
+			$ver = $obj->ver ? $obj->ver : $this->default_version;
+		}
+
+		if ( isset( $this->args[ $handle ] ) ) {
+			$ver = $ver ? $ver . '&amp;' . $this->args[ $handle ] : $this->args[ $handle ];
+		}
+
+		$src               = $obj->src;
+		$strategy          = $this->get_eligible_loading_strategy( $handle );
+		$intended_strategy = (string) $this->get_data( $handle, 'strategy' );
+		$cond_before       = '';
+		$cond_after        = '';
+		$conditional       = isset( $obj->extra['conditional'] ) ? $obj->extra['conditional'] : '';
+
+		if ( ! $this->is_delayed_strategy( $intended_strategy ) ) {
+			$intended_strategy = '';
+		}
+
+		/*
+		 * Move this script to the footer if:
+		 * 1. The script is in the header group.
+		 * 2. The current output is the header.
+		 * 3. The intended strategy is delayed.
+		 * 4. The actual strategy is not delayed.
+		 * 5. All dependent scripts are in the footer.
+		 */
+		if (
+			0 === $group &&
+			0 === $this->groups[ $handle ] &&
+			$intended_strategy &&
+			! $this->is_delayed_strategy( $strategy ) &&
+			$this->are_all_dependents_in_footer( $handle )
+		) {
+			$this->in_footer[] = $handle;
+			return false;
+		}
+
+		if ( $conditional ) {
+			$cond_before = "<!--[if {$conditional}]>\n";
+			$cond_after  = "<![endif]-->\n";
+		}
+
+		$before_script = $this->get_inline_script_tag( $handle, 'before' );
+		$after_script  = $this->get_inline_script_tag( $handle, 'after' );
+
+		if ( $before_script || $after_script ) {
+			$inline_script_tag = $cond_before . $before_script . $after_script . $cond_after;
+		} else {
+			$inline_script_tag = '';
+		}
+
+		/*
+		 * Prevent concatenation of scripts if the text domain is defined
+		 * to ensure the dependency order is respected.
+		 */
+		$translations_stop_concat = ! empty( $obj->textdomain );
+
+		$translations = $this->print_translations( $handle, false );
+		if ( $translations ) {
+			$translations = wp_get_inline_script_tag( $translations, array( 'id' => "{$handle}-js-translations" ) );
+		}
+
+		if ( $this->do_concat ) {
+			/**
+			 * Filters the script loader source.
+			 *
+			 * @since 2.2.0
+			 *
+			 * @param string $src    Script loader source path.
+			 * @param string $handle Script handle.
+			 */
+			$srce = apply_filters( 'script_loader_src', $src, $handle );
+
+			if (
+				$this->in_default_dir( $srce )
+				&& ( $before_script || $after_script || $translations_stop_concat || $this->is_delayed_strategy( $strategy ) )
+			) {
+				$this->do_concat = false;
+
+				// Have to print the so-far concatenated scripts right away to maintain the right order.
+				_print_scripts();
+				$this->reset();
+			} elseif ( $this->in_default_dir( $srce ) && ! $conditional ) {
+				$this->print_code     .= $this->print_extra_script( $handle, false );
+				$this->concat         .= "$handle,";
+				$this->concat_version .= "$handle$ver";
+				return true;
+			} else {
+				$this->ext_handles .= "$handle,";
+				$this->ext_version .= "$handle$ver";
+			}
+		}
+
+		$has_conditional_data = $conditional && $this->get_data( $handle, 'data' );
+
+		if ( $has_conditional_data ) {
+			echo $cond_before;
+		}
+
+		$this->print_extra_script( $handle );
+
+		if ( $has_conditional_data ) {
+			echo $cond_after;
+		}
+
+		// A single item may alias a set of items, by having dependencies, but no source.
+		if ( ! $src ) {
+			if ( $inline_script_tag ) {
+				if ( $this->do_concat ) {
+					$this->print_html .= $inline_script_tag;
+				} else {
+					echo $inline_script_tag;
+				}
+			}
+
+			return true;
+		}
+
+		if ( ! preg_match( '|^(https?:)?//|', $src ) && ! ( $this->content_url && str_starts_with( $src, $this->content_url ) ) ) {
+			$src = $this->base_url . $src;
+		}
+
+		if ( ! empty( $ver ) ) {
+			$src = add_query_arg( 'ver', $ver, $src );
+		}
+
+		/** This filter is documented in wp-includes/class-wp-scripts.php */
+		$src = esc_url_raw( apply_filters( 'script_loader_src', $src, $handle ) );
+
+		if ( ! $src ) {
+			return true;
+		}
+
+		$attr = array(
+			'src' => $src,
+			'id'  => "{$handle}-js",
+		);
+		if ( $strategy ) {
+			$attr[ $strategy ] = true;
+		}
+		if ( $intended_strategy ) {
+			$attr['data-wp-strategy'] = $intended_strategy;
+		}
+		$tag  = $translations . $cond_before . $before_script;
+		$tag .= wp_get_script_tag( $attr );
+		$tag .= $after_script . $cond_after;
+
+		/**
+		 * Filters the HTML script tag of an enqueued script.
+		 *
+		 * @since 4.1.0
+		 *
+		 * @param string $tag    The `<script>` tag for the enqueued script.
+		 * @param string $handle The script's registered handle.
+		 * @param string $src    The script's source URL.
+		 */
+		$tag = apply_filters( 'script_loader_tag', $tag, $handle, $src );
+
+		if ( $this->do_concat ) {
+			$this->print_html .= $tag;
+		} else {
+			echo $tag;
+		}
+
+		return true;
+	}
+
+	/**
+	 * Adds extra code to a registered script.
+	 *
+	 * @since 4.5.0
+	 *
+	 * @param string $handle   Name of the script to add the inline script to.
+	 *                         Must be lowercase.
+	 * @param string $data     String containing the JavaScript to be added.
+	 * @param string $position Optional. Whether to add the inline script
+	 *                         before the handle or after. Default 'after'.
+	 * @return bool True on success, false on failure.
+	 */
+	public function add_inline_script( $handle, $data, $position = 'after' ) {
+		if ( ! $data ) {
+			return false;
+		}
+
+		if ( 'after' !== $position ) {
+			$position = 'before';
+		}
+
+		$script   = (array) $this->get_data( $handle, $position );
+		$script[] = $data;
+
+		return $this->add_data( $handle, $position, $script );
+	}
+
+	/**
+	 * Prints inline scripts registered for a specific handle.
+	 *
+	 * @since 4.5.0
+	 * @deprecated 6.3.0 Use methods get_inline_script_tag() or get_inline_script_data() instead.
+	 *
+	 * @param string $handle   Name of the script to print inline scripts for.
+	 *                         Must be lowercase.
+	 * @param string $position Optional. Whether to add the inline script
+	 *                         before the handle or after. Default 'after'.
+	 * @param bool   $display  Optional. Whether to print the script tag
+	 *                         instead of just returning the script data. Default true.
+	 * @return string|false Script data on success, false otherwise.
+	 */
+	public function print_inline_script( $handle, $position = 'after', $display = true ) {
+		_deprecated_function( __METHOD__, '6.3.0', 'WP_Scripts::get_inline_script_data() or WP_Scripts::get_inline_script_tag()' );
+
+		$output = $this->get_inline_script_data( $handle, $position );
+		if ( empty( $output ) ) {
+			return false;
+		}
+
+		if ( $display ) {
+			echo $this->get_inline_script_tag( $handle, $position );
+		}
+		return $output;
+	}
+
+	/**
+	 * Gets data for inline scripts registered for a specific handle.
+	 *
+	 * @since 6.3.0
+	 *
+	 * @param string $handle   Name of the script to get data for.
+	 *                         Must be lowercase.
+	 * @param string $position Optional. Whether to add the inline script
+	 *                         before the handle or after. Default 'after'.
+	 * @return string Inline script, which may be empty string.
+	 */
+	public function get_inline_script_data( $handle, $position = 'after' ) {
+		$data = $this->get_data( $handle, $position );
+		if ( empty( $data ) || ! is_array( $data ) ) {
+			return '';
+		}
+
+		return trim( implode( "\n", $data ), "\n" );
+	}
+
+	/**
+	 * Gets tags for inline scripts registered for a specific handle.
+	 *
+	 * @since 6.3.0
+	 *
+	 * @param string $handle   Name of the script to get associated inline script tag for.
+	 *                         Must be lowercase.
+	 * @param string $position Optional. Whether to get tag for inline
+	 *                         scripts in the before or after position. Default 'after'.
+	 * @return string Inline script, which may be empty string.
+	 */
+	public function get_inline_script_tag( $handle, $position = 'after' ) {
+		$js = $this->get_inline_script_data( $handle, $position );
+		if ( empty( $js ) ) {
+			return '';
+		}
+
+		$id = "{$handle}-js-{$position}";
+
+		return wp_get_inline_script_tag( $js, compact( 'id' ) );
+	}
+
+	/**
+	 * Localizes a script, only if the script has already been added.
+	 *
+	 * @since 2.1.0
+	 *
+	 * @param string $handle      Name of the script to attach data to.
+	 * @param string $object_name Name of the variable that will contain the data.
+	 * @param array  $l10n        Array of data to localize.
+	 * @return bool True on success, false on failure.
+	 */
+	public function localize( $handle, $object_name, $l10n ) {
+		if ( 'jquery' === $handle ) {
+			$handle = 'jquery-core';
+		}
+
+		if ( is_array( $l10n ) && isset( $l10n['l10n_print_after'] ) ) { // back compat, preserve the code in 'l10n_print_after' if present.
+			$after = $l10n['l10n_print_after'];
+			unset( $l10n['l10n_print_after'] );
+		}
+
+		if ( ! is_array( $l10n ) ) {
+			_doing_it_wrong(
+				__METHOD__,
+				sprintf(
+					/* translators: 1: $l10n, 2: wp_add_inline_script() */
+					__( 'The %1$s parameter must be an array. To pass arbitrary data to scripts, use the %2$s function instead.' ),
+					'<code>$l10n</code>',
+					'<code>wp_add_inline_script()</code>'
+				),
+				'5.7.0'
+			);
+
+			if ( false === $l10n ) {
+				// This should really not be needed, but is necessary for backward compatibility.
+				$l10n = array( $l10n );
+			}
+		}
+
+		if ( is_string( $l10n ) ) {
+			$l10n = html_entity_decode( $l10n, ENT_QUOTES, 'UTF-8' );
+		} elseif ( is_array( $l10n ) ) {
+			foreach ( $l10n as $key => $value ) {
+				if ( ! is_scalar( $value ) ) {
+					continue;
+				}
+
+				$l10n[ $key ] = html_entity_decode( (string) $value, ENT_QUOTES, 'UTF-8' );
+			}
+		}
+
+		$script = "var $object_name = " . wp_json_encode( $l10n ) . ';';
+
+		if ( ! empty( $after ) ) {
+			$script .= "\n$after;";
+		}
+
+		$data = $this->get_data( $handle, 'data' );
+
+		if ( ! empty( $data ) ) {
+			$script = "$data\n$script";
+		}
+
+		return $this->add_data( $handle, 'data', $script );
+	}
+
+	/**
+	 * Sets handle group.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @see WP_Dependencies::set_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     Optional. Group level: level (int), no groups (false).
+	 *                             Default false.
+	 * @return bool Not already in the group or a lower group.
+	 */
+	public function set_group( $handle, $recursion, $group = false ) {
+		if ( isset( $this->registered[ $handle ]->args ) && 1 === $this->registered[ $handle ]->args ) {
+			$grp = 1;
+		} else {
+			$grp = (int) $this->get_data( $handle, 'group' );
+		}
+
+		if ( false !== $group && $grp > $group ) {
+			$grp = $group;
+		}
+
+		return parent::set_group( $handle, $recursion, $grp );
+	}
+
+	/**
+	 * Sets a translation textdomain.
+	 *
+	 * @since 5.0.0
+	 * @since 5.1.0 The `$domain` parameter was made optional.
+	 *
+	 * @param string $handle Name of the script to register a translation domain to.
+	 * @param string $domain Optional. Text domain. Default 'default'.
+	 * @param string $path   Optional. The full file path to the directory containing translation files.
+	 * @return bool True if the text domain was registered, false if not.
+	 */
+	public function set_translations( $handle, $domain = 'default', $path = '' ) {
+		if ( ! isset( $this->registered[ $handle ] ) ) {
+			return false;
+		}
+
+		/** @var \_WP_Dependency $obj */
+		$obj = $this->registered[ $handle ];
+
+		if ( ! in_array( 'wp-i18n', $obj->deps, true ) ) {
+			$obj->deps[] = 'wp-i18n';
+		}
+
+		return $obj->set_translations( $domain, $path );
+	}
+
+	/**
+	 * Prints translations set for a specific handle.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param string $handle  Name of the script to add the inline script to.
+	 *                        Must be lowercase.
+	 * @param bool   $display Optional. Whether to print the script
+	 *                        instead of just returning it. Default true.
+	 * @return string|false Script on success, false otherwise.
+	 */
+	public function print_translations( $handle, $display = true ) {
+		if ( ! isset( $this->registered[ $handle ] ) || empty( $this->registered[ $handle ]->textdomain ) ) {
+			return false;
+		}
+
+		$domain = $this->registered[ $handle ]->textdomain;
+		$path   = '';
+
+		if ( isset( $this->registered[ $handle ]->translations_path ) ) {
+			$path = $this->registered[ $handle ]->translations_path;
+		}
+
+		$json_translations = load_script_textdomain( $handle, $domain, $path );
+
+		if ( ! $json_translations ) {
+			return false;
+		}
+
+		$output = <<<JS
+( function( domain, translations ) {
+	var localeData = translations.locale_data[ domain ] || translations.locale_data.messages;
+	localeData[""].domain = domain;
+	wp.i18n.setLocaleData( localeData, domain );
+} )( "{$domain}", {$json_translations} );
+JS;
+
+		if ( $display ) {
+			wp_print_inline_script_tag( $output, array( 'id' => "{$handle}-js-translations" ) );
+		}
+
+		return $output;
+	}
+
+	/**
+	 * Determines script dependencies.
+	 *
+	 * @since 2.1.0
+	 *
+	 * @see WP_Dependencies::all_deps()
+	 *
+	 * @param string|string[] $handles   Item handle (string) or item handles (array of strings).
+	 * @param bool            $recursion Optional. Internal flag that function is calling itself.
+	 *                                   Default false.
+	 * @param int|false       $group     Optional. Group level: level (int), no groups (false).
+	 *                                   Default false.
+	 * @return bool True on success, false on failure.
+	 */
+	public function all_deps( $handles, $recursion = false, $group = false ) {
+		$r = parent::all_deps( $handles, $recursion, $group );
+		if ( ! $recursion ) {
+			/**
+			 * Filters the list of script dependencies left to print.
+			 *
+			 * @since 2.3.0
+			 *
+			 * @param string[] $to_do An array of script dependency handles.
+			 */
+			$this->to_do = apply_filters( 'print_scripts_array', $this->to_do );
+		}
+		return $r;
+	}
+
+	/**
+	 * Processes items and dependencies for the head group.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @see WP_Dependencies::do_items()
+	 *
+	 * @return string[] Handles of items that have been processed.
+	 */
+	public function do_head_items() {
+		$this->do_items( false, 0 );
+		return $this->done;
+	}
+
+	/**
+	 * Processes items and dependencies for the footer group.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @see WP_Dependencies::do_items()
+	 *
+	 * @return string[] Handles of items that have been processed.
+	 */
+	public function do_footer_items() {
+		$this->do_items( false, 1 );
+		return $this->done;
+	}
+
+	/**
+	 * Whether a handle's source is in a default directory.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @param string $src The source of the enqueued script.
+	 * @return bool True if found, false if not.
+	 */
+	public function in_default_dir( $src ) {
+		if ( ! $this->default_dirs ) {
+			return true;
+		}
+
+		if ( str_starts_with( $src, '/' . WPINC . '/js/l10n' ) ) {
+			return false;
+		}
+
+		foreach ( (array) $this->default_dirs as $test ) {
+			if ( str_starts_with( $src, $test ) ) {
+				return true;
+			}
+		}
+		return false;
+	}
+
+	/**
+	 * This overrides the add_data method from WP_Dependencies, to support normalizing of $args.
+	 *
+	 * @since 6.3.0
+	 *
+	 * @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 false;
+		}
+
+		if ( 'strategy' === $key ) {
+			if ( ! empty( $value ) && ! $this->is_delayed_strategy( $value ) ) {
+				_doing_it_wrong(
+					__METHOD__,
+					sprintf(
+						/* translators: 1: $strategy, 2: $handle */
+						__( 'Invalid strategy `%1$s` defined for `%2$s` during script registration.' ),
+						$value,
+						$handle
+					),
+					'6.3.0'
+				);
+				return false;
+			} elseif ( ! $this->registered[ $handle ]->src && $this->is_delayed_strategy( $value ) ) {
+				_doing_it_wrong(
+					__METHOD__,
+					sprintf(
+						/* translators: 1: $strategy, 2: $handle */
+						__( 'Cannot supply a strategy `%1$s` for script `%2$s` because it is an alias (it lacks a `src` value).' ),
+						$value,
+						$handle
+					),
+					'6.3.0'
+				);
+				return false;
+			}
+		}
+		return parent::add_data( $handle, $key, $value );
+	}
+
+	/**
+	 * Gets all dependents of a script.
+	 *
+	 * @since 6.3.0
+	 *
+	 * @param string $handle The script handle.
+	 * @return string[] Script handles.
+	 */
+	private function get_dependents( $handle ) {
+		// Check if dependents map for the handle in question is present. If so, use it.
+		if ( isset( $this->dependents_map[ $handle ] ) ) {
+			return $this->dependents_map[ $handle ];
+		}
+
+		$dependents = array();
+
+		// Iterate over all registered scripts, finding dependents of the script passed to this method.
+		foreach ( $this->registered as $registered_handle => $args ) {
+			if ( in_array( $handle, $args->deps, true ) ) {
+				$dependents[] = $registered_handle;
+			}
+		}
+
+		// Add the handles dependents to the map to ease future lookups.
+		$this->dependents_map[ $handle ] = $dependents;
+
+		return $dependents;
+	}
+
+	/**
+	 * Checks if the strategy passed is a valid delayed (non-blocking) strategy.
+	 *
+	 * @since 6.3.0
+	 *
+	 * @param string $strategy The strategy to check.
+	 * @return bool True if $strategy is one of the delayed strategies, otherwise false.
+	 */
+	private function is_delayed_strategy( $strategy ) {
+		return in_array(
+			$strategy,
+			$this->delayed_strategies,
+			true
+		);
+	}
+
+	/**
+	 * Gets the best eligible loading strategy for a script.
+	 *
+	 * @since 6.3.0
+	 *
+	 * @param string $handle The script handle.
+	 * @return string The best eligible loading strategy.
+	 */
+	private function get_eligible_loading_strategy( $handle ) {
+		$intended = (string) $this->get_data( $handle, 'strategy' );
+
+		// Bail early if there is no intended strategy.
+		if ( ! $intended ) {
+			return '';
+		}
+
+		/*
+		 * If the intended strategy is 'defer', limit the initial list of eligible
+		 * strategies, since 'async' can fallback to 'defer', but not vice-versa.
+		 */
+		$initial = ( 'defer' === $intended ) ? array( 'defer' ) : null;
+
+		$eligible = $this->filter_eligible_strategies( $handle, $initial );
+
+		// Return early once we know the eligible strategy is blocking.
+		if ( empty( $eligible ) ) {
+			return '';
+		}
+
+		return in_array( 'async', $eligible, true ) ? 'async' : 'defer';
+	}
+
+	/**
+	 * Filter the list of eligible loading strategies for a script.
+	 *
+	 * @since 6.3.0
+	 *
+	 * @param string              $handle   The script handle.
+	 * @param string[]|null       $eligible Optional. The list of strategies to filter. Default null.
+	 * @param array<string, true> $checked  Optional. An array of already checked script handles, used to avoid recursive loops.
+	 * @return string[] A list of eligible loading strategies that could be used.
+	 */
+	private function filter_eligible_strategies( $handle, $eligible = null, $checked = array() ) {
+		// If no strategies are being passed, all strategies are eligible.
+		if ( null === $eligible ) {
+			$eligible = $this->delayed_strategies;
+		}
+
+		// If this handle was already checked, return early.
+		if ( isset( $checked[ $handle ] ) ) {
+			return $eligible;
+		}
+
+		// Mark this handle as checked.
+		$checked[ $handle ] = true;
+
+		// If this handle isn't registered, don't filter anything and return.
+		if ( ! isset( $this->registered[ $handle ] ) ) {
+			return $eligible;
+		}
+
+		// If the handle is not enqueued, don't filter anything and return.
+		if ( ! $this->query( $handle, 'enqueued' ) ) {
+			return $eligible;
+		}
+
+		$is_alias          = (bool) ! $this->registered[ $handle ]->src;
+		$intended_strategy = $this->get_data( $handle, 'strategy' );
+
+		// For non-alias handles, an empty intended strategy filters all strategies.
+		if ( ! $is_alias && empty( $intended_strategy ) ) {
+			return array();
+		}
+
+		// Handles with inline scripts attached in the 'after' position cannot be delayed.
+		if ( $this->has_inline_script( $handle, 'after' ) ) {
+			return array();
+		}
+
+		// If the intended strategy is 'defer', filter out 'async'.
+		if ( 'defer' === $intended_strategy ) {
+			$eligible = array( 'defer' );
+		}
+
+		$dependents = $this->get_dependents( $handle );
+
+		// Recursively filter eligible strategies for dependents.
+		foreach ( $dependents as $dependent ) {
+			// Bail early once we know the eligible strategy is blocking.
+			if ( empty( $eligible ) ) {
+				return array();
+			}
+
+			$eligible = $this->filter_eligible_strategies( $dependent, $eligible, $checked );
+		}
+
+		return $eligible;
+	}
+
+	/**
+	 * Gets data for inline scripts registered for a specific handle.
+	 *
+	 * @since 6.3.0
+	 *
+	 * @param string $handle   Name of the script to get data for. Must be lowercase.
+	 * @param string $position The position of the inline script.
+	 * @return bool Whether the handle has an inline script (either before or after).
+	 */
+	private function has_inline_script( $handle, $position = null ) {
+		if ( $position && in_array( $position, array( 'before', 'after' ), true ) ) {
+			return (bool) $this->get_data( $handle, $position );
+		}
+
+		return (bool) ( $this->get_data( $handle, 'before' ) || $this->get_data( $handle, 'after' ) );
+	}
+
+	/**
+	 * Resets class properties.
+	 *
+	 * @since 2.8.0
+	 */
+	public function reset() {
+		$this->do_concat      = false;
+		$this->print_code     = '';
+		$this->concat         = '';
+		$this->concat_version = '';
+		$this->print_html     = '';
+		$this->ext_version    = '';
+		$this->ext_handles    = '';
+	}
+}