code: function isInstallationAlreadyPerformed(ctx) {
    var pathToInstallFlag = path.join(ctx.opts.projectRoot, 'plugins', ctx.opts.plugin.id, INSTALLATION_FLAG_FILE_NAME);
    try {
      fs.accessSync(pathToInstallFlag, fs.F_OK);
      return true;
    } catch (err) {
      return false;
    }
  }
docs: region mark that we installed npm packages 
  Check if we already executed this hook.
  
  @param {Object} ctx - cordova context
  @return {Boolean} true if already executed; otherwise - false