class Importmap::Map

def module_name_from(filename, mapping)
  # Regex explanation:
  # (?:\/|^) # Matches either / OR the start of the string
  # index   # Matches the word index
  # $       # Matches the end of the string
  #
  # Sample matches
  # index
  # folder/index
  index_regex = /(?:\/|^)index$/
  [ mapping.under, filename.to_s.remove(filename.extname).remove(index_regex).presence ].compact.join("/")
end