code: async function validateDirPath (dirPath) {
    try {
      const stats = await fs.lstat(dirPath);
      if (!stats.isDirectory()) {
        throw userError([
          'Source path must be a directory',
          ''
        ]);
      }
    } catch (error) {
      if (error.code === 'ENOENT') {
        throw userError([
          'No files or directories found at ' + dirPath,
          ''
        ]);
      }
  
      throw error;
    }
  }
docs: Validates that the given path is a directory, throwing user errors
  in other cases.
  
  @param {string} dirPath Path to validate
  
  @see userError()
  @throws Error if validation fails