code: function checkParentNodeModules(cb) {
      parentNodeModules = getParentNodeModules();
  
      // Check if a node_modules folder exists in any folder from the one above.
      // to top /.
      if (parentNodeModules.length) {
          let str;
          str = 'A "node_modules" folder was detected in ';
          str += parentNodeModules.length === 1 ? 'a parent directory: ' :
              'these parent directories: ';
          warn(str);
          parentNodeModules.forEach(dir => logList(dir));
          log();
  
          str = 'If you continue, ' + (parentNodeModules.length === 1 ?
                                       'that folder' : 'those folders');
          log(str + ' will be temporarily renamed. This');
          log('might affect only live node processes. If unsure, choose No ');
          log('and try to install nodeGame on another path.');
          log();
          if (!yes) {
              confirm('Continue? [y/n]', function(ok) {
                  if (ok) {
                      log();
                      let res = renameParentNodeModules(parentNodeModules);
                      if (res !== true) {
                          err('Could not rename ' + res[0]);
                          installationFailed();
                      }
                      log();
                      doInstall();
                  }
                  else {
                      installationAborted(true);
                      return;
                  }
              });
          }
          else {
              log('Continue? [y/n] --yes');
              log();
          }
      }
      else {
          doInstall();
      }
  }
docs: Helper functions. /////////////////////////////////////////////////////////////////////////////