@spec invalid_option!(key(), term(), String.t()) :: no_return()

Raises an ArgumentError describing an option whose value did not pass validation. expected is a human description such as "a boolean".

iex> JSV.Helpers.OptsValidator.invalid_option!(:cast, "yes", "a boolean")
** (ArgumentError) invalid value for option :cast, expected a boolean, got: "yes"

@spec unknown_option!(key()) :: no_return()

Raises an ArgumentError describing an unknown option key.

iex> JSV.Helpers.OptsValidator.unknown_option!(:bogus)
** (ArgumentError) unknown option :bogus

@spec validate(keyword(), map(), validator()) :: map()

Validates opts against fun, accumulating values into the defaults map and returning the merged map.

The validator is called as fun.(key, value) and must return the value to store. Invalid options should raise (see invalid_option!/3 and unknown_option!/1).

iex> JSV.Helpers.OptsValidator.validate([a: 1, b: 2], %{}, fn _key, value -> value*2 end)
%{a: 2, b: 4}

iex> JSV.Helpers.OptsValidator.validate([cast: false], %{cast: true}, fn _key, value -> value end)
%{cast: false}

iex> JSV.Helpers.OptsValidator.validate([{:cast, :hello}], %{}, fn key, value ->
...>   JSV.Helpers.OptsValidator.invalid_option!(key, value, "a boolean")
...> end)
** (ArgumentError) invalid value for option :cast, expected a boolean, got: :hello

iex> JSV.Helpers.OptsValidator.validate([:foo], %{cast: true}, fn _key, value -> value end)
** (ArgumentError) expected a {key, value} option tuple, got: :foo