Function optimize

plugins/plugin-optimize/plugin.js:110–181

({buildDirectory})

  return {
    name: '@snowpack/plugin-optimize',
    async optimize({buildDirectory}) {
      // 0. setup
      await init;
      let generatedFiles = {};

      // 1. index files
      const allFiles = glob
        .sync('**/*', {
          cwd: buildDirectory,
          ignore: [`${config.buildOptions.metaUrlPath}/*`],
          nodir: true,
        })
        .map((file) => path.join(buildDirectory, file)); // resolve to root dir

      // 2. scan imports
      const manifest = await scanHTML(
        allFiles.filter((f) => path.extname(f) === '.html'),
        buildDirectory,
      );
      let preloadCSS = false; // only bother preloading CSS if option is enabled AND there are .css.proxy.js files
      if (options.preloadCSS) {
        for (f in manifest) {
          if (
            manifest[f].js &&
            manifest[f].js.findIndex((js) => js.endsWith('.css.proxy.js')) !== -1
          ) {
            preloadCSS = true;
            break;
          }
        }
      }

      // 3. optimize all files in parallel
      const parallelWorkQueue = new PQueue({concurrency: CONCURRENT_WORKERS});
      allFiles
        .filter(
          (file) => (preloadCSS ? !file.endsWith('.css.proxy.js') : true), // if preloading CSS, don’t optimize .css.proxy.js files
        )
        .forEach((file) => {
          parallelWorkQueue.add(() =>
            optimizeFile({
              file,
              preloadCSS,
              rootDir: buildDirectory,
              target: options.target,
            }).catch((err) => {
              log(`Error: ${file} ${err.toString()}`, 'error');
            }),
          );
        });
      await parallelWorkQueue.onIdle();

      // 5. build CSS file
      if (preloadCSS) {
        const combinedCSS = buildImportCSS(manifest, options.minifyCSS);
        const outputCSS = path.join(buildDirectory, options.preloadCSSFileName);
        await mkdirp(path.dirname(outputCSS));
        fs.writeFileSync(outputCSS, combinedCSS, 'utf-8');