Use higher JS optimization level in release builds

Author: parlough

site/build.yaml

@@ -7,3 +7,23 @@ builders:
         - "lib/src/style_hash.dart"
     auto_apply: root_package
     build_to: source
+
+targets:
+  $default:
+    builders:
+      build_web_compilers:entrypoint:
+        dev_options:
+          compilers:
+            dartdevc:
+        release_options:
+          # Use production compilers for release builds and
+          # ensure kReleaseMode in jaspr is enabled.
+          compilers:
+            dart2js:
+              args:
+                - --no-source-maps
+                - -O4
+                - -Djaspr.flags.release=true
+            # Disable for now.
+            # dart2wasm:
+            #   args: [-O2, -Djaspr.flags.release=true]

site/lib/src/style_hash.dart

@@ -2,4 +2,4 @@
 // dart format off
 
 /// The generated hash of the `main.css` file.
-const generatedStylesHash = 'nvTevrLjFn98';
+const generatedStylesHash = 'ugxj95DjrnBJ';

tool/dash_site/lib/src/commands/build.dart

@@ -43,6 +43,9 @@ final class BuildSiteCommand extends Command<int> {
         'run',
         'jaspr_cli:jaspr',
         'build',
+        // Use build_web_compiler options specified in build.yaml instead of
+        // those specified by jaspr_cli.
+        '--no-managed-build-options',
         '--sitemap-domain=https://docs.flutter.dev',
         '--dart-define=PRODUCTION=$productionRelease',
       ],

tool/dash_site/lib/src/commands/serve.dart

@@ -15,8 +15,18 @@ final class ServeSiteCommand extends Command<int> {
   @override
   String get name => 'serve';
 
+  ServeSiteCommand() {
+    argParser.addFlag(
+      'release',
+      defaultsTo: false,
+      help: 'Build with compilers used for release builds instead of dartdevc.',
+    );
+  }
+
   @override
   Future<int> run() async {
+    final release = argResults!.flag('release');
+
     installJasprCliIfNecessary();
 
     final process = await Process.start(
@@ -27,7 +37,11 @@ final class ServeSiteCommand extends Command<int> {
         'run',
         'jaspr_cli:jaspr',
         'serve',
+        // Use build_web_compiler options specified in build.yaml instead of
+        // those specified by jaspr_cli.
+        '--no-managed-build-options',
         '--dart-define=PRODUCTION=false',
+        if (release) '--release',
       ],
       workingDirectory: 'site',
       runInShell: true,