Use print_scripts_array filter instead of wp_print_scripts action

WordPress · westonruter · Sep 27, 2024 · Aug 25, 2024 · Aug 25, 2024 · Aug 25, 2024
commit 0c2d7b23b70b4ede5abc30ff54e922e3594ba97d
diff --git a/plugins/web-worker-offloading/hooks.php b/plugins/web-worker-offloading/hooks.php
@@ -70,30 +70,35 @@ function wwo_register_default_scripts( WP_Scripts $scripts ): void {
 add_action( 'wp_default_scripts', 'wwo_register_default_scripts' );
 
 /**
- * Adds `web-worker-offloading` as dependency to scripts with `worker` data. Also, marks their strategy as `async`.
+ * Prepends web-worker-offloading to the list of scripts to print if one of the queued scripts is offloaded to a worker.
  *
- * This is needed because scripts offloaded to a worker thread can be considered async. However, they may include `before` and `after` inline
- * scripts that need sequential execution. Once marked as async, `filter_eligible_strategies()` determines if the
- * script is eligible for async execution. If so, it will be offloaded to the worker thread.
+ * This also marks their strategy as `async`. This is needed because scripts offloaded to a worker thread can be
+ * considered async. However, they may include `before` and `after` inline scripts that need sequential execution. Once
+ * marked as async, `filter_eligible_strategies()` determines if the script is eligible for async execution. If so, it
+ * will be offloaded to the worker thread.
  *
- * @since n.e.x.t
+ * @since 0.1.0
+ *
+ * @param string[]|mixed $to_do An array of enqueued script dependency handles.
+ * @return string[] Script handles.
  */
-function wwo_update_worker_scripts_deps_and_strategy(): void {
-	foreach ( wp_scripts()->registered as $dep ) {
-		if (
-			(bool) wp_scripts()->get_data( $dep->handle, 'worker' ) &&
-			! in_array( 'web-worker-offloading', wp_scripts()->registered[ $dep->handle ]->deps, true )
-		) {
-			wp_scripts()->registered[ $dep->handle ]->deps[] = 'web-worker-offloading';
+function wwo_filter_print_scripts_array( $to_do ): array {
+	$scripts = wp_scripts();
+	foreach ( (array) $to_do as $handle ) {
+		if ( true === $scripts->get_data( $handle, 'worker' ) ) {
+			$scripts->set_group( 'web-worker-offloading', false, 0 ); // Try to print in the head.
+			array_unshift( $to_do, 'web-worker-offloading' );
 
-			if ( false === wp_scripts()->get_data( $dep->handle, 'strategy' ) ) {
-				wp_script_add_data( $dep->handle, 'strategy', 'async' ); // The 'defer' strategy would work as well.
-				wp_script_add_data( $dep->handle, 'wwo_strategy_added', true );
+			// TODO: This should be reconsidered because scripts needing to be offloaded will often have after scripts. See <https://github.com/WordPress/performance/pull/1497/files#r1733538721>.
+			if ( false === wp_scripts()->get_data( $handle, 'strategy' ) ) {
+				wp_script_add_data( $handle, 'strategy', 'async' ); // The 'defer' strategy would work as well.
+				wp_script_add_data( $handle, 'wwo_strategy_added', true );
 			}
 		}
 	}
+	return $to_do;
 }
-add_action( 'wp_print_scripts', 'wwo_update_worker_scripts_deps_and_strategy' );
+add_filter( 'print_scripts_array', 'wwo_filter_print_scripts_array' );
 
 /**
  * Updates script type for handles having `web-worker-offloading` as dependency.

diff --git a/plugins/web-worker-offloading/tests/test-web-worker-offloading.php b/plugins/web-worker-offloading/tests/test-web-worker-offloading.php
@@ -178,7 +178,7 @@ public static function data_update_script_types(): array {
 	 * Test `wwo_update_script_type`.
 	 *
 	 * @covers ::wwo_update_script_type
-	 * @covers ::wwo_update_worker_scripts_deps_and_strategy
+	 * @covers ::wwo_filter_print_scripts_array
 	 *
 	 * @dataProvider data_update_script_types
 	 *
@@ -187,19 +187,7 @@ public static function data_update_script_types(): array {
 	 * @param bool    $doing_it_wrong Whether to expect a `_doing_it_wrong` notice.
 	 */
 	public function test_update_script_types( Closure $set_up, string $expected, bool $doing_it_wrong ): void {
-		$wwo_config_data        = wp_scripts()->get_inline_script_data( 'web-worker-offloading', 'before' );
-		$wwo_inline_script_data = wp_scripts()->get_inline_script_data( 'web-worker-offloading', 'after' );
-
-		$expected = str_replace(
-			'{{ wwo_config }}',
-			wp_get_inline_script_tag( $wwo_config_data, array( 'id' => 'web-worker-offloading-js-before' ) ),
-			$expected
-		);
-		$expected = str_replace(
-			'{{ wwo_inline_script }}',
-			wp_get_inline_script_tag( $wwo_inline_script_data, array( 'id' => 'web-worker-offloading-js-after' ) ),
-			$expected
-		);
+		$expected = $this->replace_placeholders( $expected );
 
 		if ( $doing_it_wrong ) {
 			$this->setExpectedIncorrectUsage( 'wwo_update_script_type' );
@@ -214,6 +202,53 @@ public function test_update_script_types( Closure $set_up, string $expected, boo
 		$this->assertEquals( $expected, $actual );
 	}
 
+
+	/**
+	 * Test head and footer scripts.
+	 *
+	 * @covers ::wwo_update_script_type
+	 * @covers ::wwo_filter_print_scripts_array
+	 */
+	public function test_head_and_footer_scripts(): void {
+		wp_enqueue_script( 'foo', 'https://example.com/foo.js', array(), '1.0.0', false );
+		wp_script_add_data( 'foo', 'worker', true );
+
+		$this->assertEquals(
+			$this->replace_placeholders( '{{ wwo_config }}{{ wwo_inline_script }}<script type="text/partytown" src="https://example.com/foo.js?ver=1.0.0" id="foo-js"  ></script>' ),
+			trim( get_echo( 'wp_print_head_scripts' ) )
+		);
+
+		wp_enqueue_script( 'bar', 'https://example.com/bar.js', array(), '1.0.0', true );
+		wp_script_add_data( 'bar', 'worker', true );
+
+		$this->assertEquals(
+			$this->replace_placeholders( '<script type="text/partytown" src="https://example.com/bar.js?ver=1.0.0" id="bar-js"  ></script>' ),
+			trim( get_echo( 'wp_print_footer_scripts' ) )
+		);
+	}
+
+	/**
+	 * Replace placeholders.
+	 *
+	 * @param string $template Template.
+	 * @return string Template with placeholders replaced.
+	 */
+	private function replace_placeholders( string $template ): string {
+		$wwo_config_data        = wp_scripts()->get_inline_script_data( 'web-worker-offloading', 'before' );
+		$wwo_inline_script_data = wp_scripts()->get_inline_script_data( 'web-worker-offloading', 'after' );
+
+		$template = str_replace(
+			'{{ wwo_config }}',
+			wp_get_inline_script_tag( $wwo_config_data, array( 'id' => 'web-worker-offloading-js-before' ) ),
+			$template
+		);
+		return str_replace(
+			'{{ wwo_inline_script }}',
+			wp_get_inline_script_tag( $wwo_inline_script_data, array( 'id' => 'web-worker-offloading-js-after' ) ),
+			$template
+		);
+	}
+
 	/**
 	 * Reset WP_Scripts and WP_Styles.
 	 */