code: function findExcess(dir, shrinkwrap, opts, scope, cb) {  // jshint ignore:line
      fs.readdir(dir, function (err, files) {
          if (err) {
              return cb(err);
          }
  
          parallel(files.map(function (file) {
              return validateExcess.bind(null, dir, file, shrinkwrap, opts,
                scope);
          }), function (err, excessFiles) {
              if (err) {
                  return cb(err);
              }
              return cb(null, flatten(excessFiles || []).filter(Boolean));
          });
      });
  }
docs: /* find any excess folders in node_modules that are not in
  deps.