whole_func_string: function filesUnder (rootDir) {
    return directoryContents(
      rootDir,
      stats => (stats.isFile() && stats.size !== 0),
      (path, stats) => [path, stats.size]
    )
  }
func_code_string: function filesUnder (rootDir) {
    return directoryContents(
      rootDir,
      stats => (stats.isFile() && stats.size !== 0),
      (path, stats) => [path, stats.size]
    )
  }
func_documentation_string: directoriesUnder