Specs

to_string(
  Calendar.datetime() | nil,
  Calendar.datetime() | nil,
  Cldr.backend(),
  Keyword.t()
) :: {:ok, String.t()} | {:error, {module(), String.t()}}

Returns a localised string representing the formatted interval formed by two dates.

Arguments

• from is any map that conforms to the Calendar.datetime type.

• to is any map that conforms to the Calendar.datetime type. to must occur on or after from.

• backend is any module that includes use Cldr and is therefore a Cldr backend module

• options is a keyword list of options. The default is [].

Either of from or to may also be nil in which case the result is an "open" interval and the non-nil parameter is formatted using Cldr.DateTime.to_string/3.

Options

• :format is one of :short, :medium or :long or a specific format type or a string representing of an interval format. The default is :medium.

• locale is any valid locale name returned by Cldr.known_locale_names/0 or a Cldr.LanguageTag struct. The default is Cldr.get_locale/0

• number_system: a number system into which the formatted date digits should be transliterated

Returns

• {:ok, string} or

• {:error, {exception, reason}}

Notes

• For more information on interval format string see the Cldr.Interval.

• The available predefined formats that can be applied are the keys of the map returned by Cldr.DateTime.Format.interval_formats("en", :gregorian) where "en" can be replaced by any configuration locale name and :gregorian is the underlying CLDR calendar type.

• In the case where from and to are equal, a single date is formatted instead of an interval

Examples

iex> Cldr.DateTime.Interval.to_string ~U[2020-01-01 00:00:00.0Z],
...> ~U[2020-12-31 10:00:00.0Z], MyApp.Cldr
{:ok, "Jan 1, 2020, 12:00:00 AM – Dec 31, 2020, 10:00:00 AM"}

iex> Cldr.DateTime.Interval.to_string ~U[2020-01-01 00:00:00.0Z], nil, MyApp.Cldr
{:ok, "Jan 1, 2020, 12:00:00 AM –"}