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   1  <?php
   2  /**
   3   * Script Modules API: WP_Script_Modules class.
   4   *
   5   * Native support for ES Modules and Import Maps.
   6   *
   7   * @package WordPress
   8   * @subpackage Script Modules
   9   */
  10  
  11  /**
  12   * Core class used to register script modules.
  13   *
  14   * @since 6.5.0
  15   */
  16  class WP_Script_Modules {
  17      /**
  18       * Holds the registered script modules, keyed by script module identifier.
  19       *
  20       * @since 6.5.0
  21       * @var array
  22       */
  23      private $registered = array();
  24  
  25      /**
  26       * Holds the script module identifiers that were enqueued before registered.
  27       *
  28       * @since 6.5.0
  29       * @var array<string, true>
  30       */
  31      private $enqueued_before_registered = array();
  32  
  33      /**
  34       * Registers the script module if no script module with that script module
  35       * identifier has already been registered.
  36       *
  37       * @since 6.5.0
  38       *
  39       * @param string            $id       The identifier of the script module. Should be unique. It will be used in the
  40       *                                    final import map.
  41       * @param string            $src      Optional. Full URL of the script module, or path of the script module relative
  42       *                                    to the WordPress root directory. If it is provided and the script module has
  43       *                                    not been registered yet, it will be registered.
  44       * @param array             $deps     {
  45       *                                        Optional. List of dependencies.
  46       *
  47       *                                        @type string|array ...$0 {
  48       *                                            An array of script module identifiers of the dependencies of this script
  49       *                                            module. The dependencies can be strings or arrays. If they are arrays,
  50       *                                            they need an `id` key with the script module identifier, and can contain
  51       *                                            an `import` key with either `static` or `dynamic`. By default,
  52       *                                            dependencies that don't contain an `import` key are considered static.
  53       *
  54       *                                            @type string $id     The script module identifier.
  55       *                                            @type string $import Optional. Import type. May be either `static` or
  56       *                                                                 `dynamic`. Defaults to `static`.
  57       *                                        }
  58       *                                    }
  59       * @param string|false|null $version  Optional. String specifying the script module version number. Defaults to false.
  60       *                                    It is added to the URL as a query string for cache busting purposes. If $version
  61       *                                    is set to false, the version number is the currently installed WordPress version.
  62       *                                    If $version is set to null, no version is added.
  63       */
  64  	public function register( string $id, string $src, array $deps = array(), $version = false ) {
  65          if ( ! isset( $this->registered[ $id ] ) ) {
  66              $dependencies = array();
  67              foreach ( $deps as $dependency ) {
  68                  if ( is_array( $dependency ) ) {
  69                      if ( ! isset( $dependency['id'] ) ) {
  70                          _doing_it_wrong( __METHOD__, __( 'Missing required id key in entry among dependencies array.' ), '6.5.0' );
  71                          continue;
  72                      }
  73                      $dependencies[] = array(
  74                          'id'     => $dependency['id'],
  75                          'import' => isset( $dependency['import'] ) && 'dynamic' === $dependency['import'] ? 'dynamic' : 'static',
  76                      );
  77                  } elseif ( is_string( $dependency ) ) {
  78                      $dependencies[] = array(
  79                          'id'     => $dependency,
  80                          'import' => 'static',
  81                      );
  82                  } else {
  83                      _doing_it_wrong( __METHOD__, __( 'Entries in dependencies array must be either strings or arrays with an id key.' ), '6.5.0' );
  84                  }
  85              }
  86  
  87              $this->registered[ $id ] = array(
  88                  'src'          => $src,
  89                  'version'      => $version,
  90                  'enqueue'      => isset( $this->enqueued_before_registered[ $id ] ),
  91                  'dependencies' => $dependencies,
  92              );
  93          }
  94      }
  95  
  96      /**
  97       * Marks the script module to be enqueued in the page.
  98       *
  99       * If a src is provided and the script module has not been registered yet, it
 100       * will be registered.
 101       *
 102       * @since 6.5.0
 103       *
 104       * @param string            $id       The identifier of the script module. Should be unique. It will be used in the
 105       *                                    final import map.
 106       * @param string            $src      Optional. Full URL of the script module, or path of the script module relative
 107       *                                    to the WordPress root directory. If it is provided and the script module has
 108       *                                    not been registered yet, it will be registered.
 109       * @param array             $deps     {
 110       *                                        Optional. List of dependencies.
 111       *
 112       *                                        @type string|array ...$0 {
 113       *                                            An array of script module identifiers of the dependencies of this script
 114       *                                            module. The dependencies can be strings or arrays. If they are arrays,
 115       *                                            they need an `id` key with the script module identifier, and can contain
 116       *                                            an `import` key with either `static` or `dynamic`. By default,
 117       *                                            dependencies that don't contain an `import` key are considered static.
 118       *
 119       *                                            @type string $id     The script module identifier.
 120       *                                            @type string $import Optional. Import type. May be either `static` or
 121       *                                                                 `dynamic`. Defaults to `static`.
 122       *                                        }
 123       *                                    }
 124       * @param string|false|null $version  Optional. String specifying the script module version number. Defaults to false.
 125       *                                    It is added to the URL as a query string for cache busting purposes. If $version
 126       *                                    is set to false, the version number is the currently installed WordPress version.
 127       *                                    If $version is set to null, no version is added.
 128       */
 129  	public function enqueue( string $id, string $src = '', array $deps = array(), $version = false ) {
 130          if ( isset( $this->registered[ $id ] ) ) {
 131              $this->registered[ $id ]['enqueue'] = true;
 132          } elseif ( $src ) {
 133              $this->register( $id, $src, $deps, $version );
 134              $this->registered[ $id ]['enqueue'] = true;
 135          } else {
 136              $this->enqueued_before_registered[ $id ] = true;
 137          }
 138      }
 139  
 140      /**
 141       * Unmarks the script module so it will no longer be enqueued in the page.
 142       *
 143       * @since 6.5.0
 144       *
 145       * @param string $id The identifier of the script module.
 146       */
 147  	public function dequeue( string $id ) {
 148          if ( isset( $this->registered[ $id ] ) ) {
 149              $this->registered[ $id ]['enqueue'] = false;
 150          }
 151          unset( $this->enqueued_before_registered[ $id ] );
 152      }
 153  
 154      /**
 155       * Removes a registered script module.
 156       *
 157       * @since 6.5.0
 158       *
 159       * @param string $id The identifier of the script module.
 160       */
 161  	public function deregister( string $id ) {
 162          unset( $this->registered[ $id ] );
 163          unset( $this->enqueued_before_registered[ $id ] );
 164      }
 165  
 166      /**
 167       * Adds the hooks to print the import map, enqueued script modules and script
 168       * module preloads.
 169       *
 170       * In classic themes, the script modules used by the blocks are not yet known
 171       * when the `wp_head` actions is fired, so it needs to print everything in the
 172       * footer.
 173       *
 174       * @since 6.5.0
 175       */
 176  	public function add_hooks() {
 177          $position = wp_is_block_theme() ? 'wp_head' : 'wp_footer';
 178          add_action( $position, array( $this, 'print_import_map' ) );
 179          add_action( $position, array( $this, 'print_enqueued_script_modules' ) );
 180          add_action( $position, array( $this, 'print_script_module_preloads' ) );
 181      }
 182  
 183      /**
 184       * Prints the enqueued script modules using script tags with type="module"
 185       * attributes.
 186       *
 187       * @since 6.5.0
 188       */
 189  	public function print_enqueued_script_modules() {
 190          foreach ( $this->get_marked_for_enqueue() as $id => $script_module ) {
 191              wp_print_script_tag(
 192                  array(
 193                      'type' => 'module',
 194                      'src'  => $this->get_src( $id ),
 195                      'id'   => $id . '-js-module',
 196                  )
 197              );
 198          }
 199      }
 200  
 201      /**
 202       * Prints the the static dependencies of the enqueued script modules using
 203       * link tags with rel="modulepreload" attributes.
 204       *
 205       * If a script module is marked for enqueue, it will not be preloaded.
 206       *
 207       * @since 6.5.0
 208       */
 209  	public function print_script_module_preloads() {
 210          foreach ( $this->get_dependencies( array_keys( $this->get_marked_for_enqueue() ), array( 'static' ) ) as $id => $script_module ) {
 211              // Don't preload if it's marked for enqueue.
 212              if ( true !== $script_module['enqueue'] ) {
 213                  echo sprintf(
 214                      '<link rel="modulepreload" href="%s" id="%s">',
 215                      esc_url( $this->get_src( $id ) ),
 216                      esc_attr( $id . '-js-modulepreload' )
 217                  );
 218              }
 219          }
 220      }
 221  
 222      /**
 223       * Prints the import map using a script tag with a type="importmap" attribute.
 224       *
 225       * @since 6.5.0
 226       *
 227       * @global WP_Scripts $wp_scripts The WP_Scripts object for printing the polyfill.
 228       */
 229  	public function print_import_map() {
 230          $import_map = $this->get_import_map();
 231          if ( ! empty( $import_map['imports'] ) ) {
 232              global $wp_scripts;
 233              if ( isset( $wp_scripts ) ) {
 234                  wp_print_inline_script_tag(
 235                      wp_get_script_polyfill(
 236                          $wp_scripts,
 237                          array(
 238                              'HTMLScriptElement.supports && HTMLScriptElement.supports("importmap")' => 'wp-polyfill-importmap',
 239                          )
 240                      ),
 241                      array(
 242                          'id' => 'wp-load-polyfill-importmap',
 243                      )
 244                  );
 245              }
 246              wp_print_inline_script_tag(
 247                  wp_json_encode( $import_map, JSON_HEX_TAG | JSON_HEX_AMP ),
 248                  array(
 249                      'type' => 'importmap',
 250                      'id'   => 'wp-importmap',
 251                  )
 252              );
 253          }
 254      }
 255  
 256      /**
 257       * Returns the import map array.
 258       *
 259       * @since 6.5.0
 260       *
 261       * @return array Array with an `imports` key mapping to an array of script module identifiers and their respective
 262       *               URLs, including the version query.
 263       */
 264  	private function get_import_map(): array {
 265          $imports = array();
 266          foreach ( $this->get_dependencies( array_keys( $this->get_marked_for_enqueue() ) ) as $id => $script_module ) {
 267              $imports[ $id ] = $this->get_src( $id );
 268          }
 269          return array( 'imports' => $imports );
 270      }
 271  
 272      /**
 273       * Retrieves the list of script modules marked for enqueue.
 274       *
 275       * @since 6.5.0
 276       *
 277       * @return array Script modules marked for enqueue, keyed by script module identifier.
 278       */
 279  	private function get_marked_for_enqueue(): array {
 280          $enqueued = array();
 281          foreach ( $this->registered as $id => $script_module ) {
 282              if ( true === $script_module['enqueue'] ) {
 283                  $enqueued[ $id ] = $script_module;
 284              }
 285          }
 286          return $enqueued;
 287      }
 288  
 289      /**
 290       * Retrieves all the dependencies for the given script module identifiers,
 291       * filtered by import types.
 292       *
 293       * It will consolidate an array containing a set of unique dependencies based
 294       * on the requested import types: 'static', 'dynamic', or both. This method is
 295       * recursive and also retrieves dependencies of the dependencies.
 296       *
 297       * @since 6.5.0
 298       *
 299  
 300       * @param string[] $ids          The identifiers of the script modules for which to gather dependencies.
 301       * @param array    $import_types Optional. Import types of dependencies to retrieve: 'static', 'dynamic', or both.
 302       *                               Default is both.
 303       * @return array List of dependencies, keyed by script module identifier.
 304       */
 305  	private function get_dependencies( array $ids, array $import_types = array( 'static', 'dynamic' ) ) {
 306          return array_reduce(
 307              $ids,
 308              function ( $dependency_script_modules, $id ) use ( $import_types ) {
 309                  $dependencies = array();
 310                  foreach ( $this->registered[ $id ]['dependencies'] as $dependency ) {
 311                      if (
 312                      in_array( $dependency['import'], $import_types, true ) &&
 313                      isset( $this->registered[ $dependency['id'] ] ) &&
 314                      ! isset( $dependency_script_modules[ $dependency['id'] ] )
 315                      ) {
 316                          $dependencies[ $dependency['id'] ] = $this->registered[ $dependency['id'] ];
 317                      }
 318                  }
 319                  return array_merge( $dependency_script_modules, $dependencies, $this->get_dependencies( array_keys( $dependencies ), $import_types ) );
 320              },
 321              array()
 322          );
 323      }
 324  
 325      /**
 326       * Gets the versioned URL for a script module src.
 327       *
 328       * If $version is set to false, the version number is the currently installed
 329       * WordPress version. If $version is set to null, no version is added.
 330       * Otherwise, the string passed in $version is used.
 331       *
 332       * @since 6.5.0
 333       *
 334       * @param string $id The script module identifier.
 335       * @return string The script module src with a version if relevant.
 336       */
 337  	private function get_src( string $id ): string {
 338          if ( ! isset( $this->registered[ $id ] ) ) {
 339              return '';
 340          }
 341  
 342          $script_module = $this->registered[ $id ];
 343          $src           = $script_module['src'];
 344  
 345          if ( false === $script_module['version'] ) {
 346              $src = add_query_arg( 'ver', get_bloginfo( 'version' ), $src );
 347          } elseif ( null !== $script_module['version'] ) {
 348              $src = add_query_arg( 'ver', $script_module['version'], $src );
 349          }
 350  
 351          /**
 352           * Filters the script module source.
 353           *
 354           * @since 6.5.0
 355           *
 356           * @param string $src Module source url.
 357           * @param string $id  Module identifier.
 358           */
 359          $src = apply_filters( 'script_module_loader_src', $src, $id );
 360  
 361          return $src;
 362      }
 363  }