code: function buildApp(src, dest, options, callback) {
    const appArgs = selectAppArgs(options);
    copy(src, dest, (error) => {
      if (error) {
        callback(`Error Copying temporary directory: ${error}`);
        return;
      }
  
      fs.writeFileSync(
        path.join(dest, '/nativefier.json'),
        JSON.stringify(appArgs),
      );
  
      maybeCopyScripts(options.inject, dest)
        .catch((err) => {
          log.warn(err);
        })
        .then(() => {
          changeAppPackageJsonName(dest, appArgs.name, appArgs.targetUrl);
          callback();
        });
    });
  }
docs: Creates a temporary directory and copies the './app folder' inside,
  and adds a text file with the configuration for the single page app.
  
  @param {string} src
  @param {string} dest
  @param {{}} options
  @param callback