rules/directory-index/index.js
function(filePath, opts) {
  if (filePath.isDirectory) {
    return true;
  }

  if (!check(opts).has('ignore') || check(opts.ignore).is.not('array')) {
    return false;
  }

  return opts.ignore.some(function(directory) {
    return _.isString(directory) && directory === filePath.relative ||
           _.isRegExp(directory) && directory.test(filePath.relative);
  });

}
function(filePath, opts) {
  if (filePath.isDirectory) {
    return true;
  }

  if (!check(opts).has('ignore') || check(opts.ignore).is.not('array')) {
    return false;
  }

  return opts.ignore.some(function(directory) {
    return _.isString(directory) && directory === filePath.relative ||
           _.isRegExp(directory) && directory.test(filePath.relative);
  });

}
/*
filePathCanBeIgnored

Check if file path can be ignored as needing to contain index file.