Recently we upgraded to Gulp 4. However, the following things still need to be addressed in some way:

- If a task series is executed with an anonymous function inside it, we'll see `Starting '<anonymous>'` in the output, which isn't that great. We need to either suppress it or use named functions.
- If a task is private, it should be hidden in some way. For example, `gh-pages-prepare` is only used in the public `web` target and should not be used on its own, however currently it shows in the default `gulp` output since it's a regular task. Perhaps we should mark them with an underscore?
compress: {
      
      sequences: false,
    },
    keep_classnames: true,
    keep_fnames: true,
  };
  fs.writeFileSync(
    dir + "/web/pdf.viewer.js",
    (await Terser.minify(viewerFiles, options)).code
  );
  fs.writeFileSync(
    dir + "/build/pdf.min.js",
    (await Terser.minify(pdfFile, options)).code
  );
  fs.writeFileSync(
    dir + "/build/pdf.worker.min.js",
    (await Terser.minify(pdfWorkerFile, options)).code
  );
  fs.writeFileSync(
    dir + "/build/pdf.sandbox.min.js",
    (await Terser.minify(pdfSandboxFile, options)).code
  );
  fs.writeFileSync(
    dir + "image_decoders/pdf.image_decoders.min.js",
    (await Terser.minify(pdfImageDecodersFile, options)).code
  );
  console.log();
  console.log("### Cleaning js files");
  fs.unlinkSync(dir + "/web/viewer.js");