code: function validateExcess(dir, file, shrinkwrap, opts, scope, cb) {  // jshint ignore:line
      file = file.toLowerCase();
  
      // don't consider node_modules/.bin
      if (file === '.bin') {
          return cb();
      }
  
      // consider top-level scoped packages only; e.g. those nested at the level
      // node_modules/{*}
      var isScopedDir = file[0] === '@';
      if (isScopedDir) {
          return findExcess(path.join(dir, scope + '/' + file), shrinkwrap, opts,
            file, cb);
      }
  
      // the file is in excess if it does not exist in the package.json's
      // dev dependencies; this step is skipped if we are not analyzing
      // dev dependencies
      if (opts.dev && shrinkwrap.devDependencies &&
          lowercaseContains(Object.keys(shrinkwrap.devDependencies), file)) {
          return cb();
      }
  
      // the file is in excess if it does not exist in the package.json's
      // regular dependencies
      if (shrinkwrap.dependencies && lowercaseContains(Object.keys(shrinkwrap.dependencies), file)) {
          return cb();
      }
  
      // if all checks pass up until this point, the file is in excess
      return cb(null, [file]);
  }
docs: /* find any excess folders in node_modules that are not in
  deps.