perf: Improve performance by running async tasks concurrently

build-system/tasks/dist.js

@@ -210,17 +210,17 @@ function buildLoginDone(version) {
 async function buildWebPushPublisherFiles() {
   const distDir = 'dist/v0';
   for (const version of WEB_PUSH_PUBLISHER_VERSIONS) {
-    for (const fileName of WEB_PUSH_PUBLISHER_FILES) {
+    await Promise.all(WEB_PUSH_PUBLISHER_FILES.map((fileName) => {
       const tempBuildDir = `build/all/amp-web-push-${version}`;
       const builtName = `${fileName}.js`;
       const minifiedName = maybeToEsmName(builtName);
-      await compileJs(`./${tempBuildDir}`, builtName, `./${distDir}`, {
+      return compileJs(`./${tempBuildDir}`, builtName, `./${distDir}`, {
         watch: argv.watch,
         includePolyfills: true,
         minify: true,
         minifiedName,
       });
-    }
+    }));
   }
   await postBuildWebPushPublisherFilesVersion();
 }
@@ -284,8 +284,10 @@ async function postBuildWebPushPublisherFilesVersion() {
       }
 
       // Build Helper Frame HTML
-      const html = await fs.readFile(`${basePath}/${fileName}.html`, 'utf8');
-      const js = await fs.readFile(minifiedFile, 'utf8');
+      const [html, js] = await Promise.all([
+        fs.readFile(`${basePath}/${fileName}.html`, 'utf8'),
+        fs.readFile(minifiedFile, 'utf8')
+      ]);
       const minifiedHtml = html.replace(
         `<!-- [REPLACE-SENTINEL ${fileName}.js] -->`,
         `<script>${js}</script>`