code: function shouldBeIncluded(file) {
  
    if (!showAllFiles && file[0] === '.') {
      return false
    }
    if (hasExcludePattern) {
      return !excludePattern.test(file)
    }
    if (hasIncludePattern) {
      return includePattern.test(file)
    }
    return true
  }
docs: Uses either the exclude or include pattern to determine
  if a file should be shown.
  @param {String} file   filename