Specs

get_and_update!(
  t(),
  key(),
  (value() | nil -> {current_value, new_value :: value()} | :pop)
) :: {current_value, new_keywords :: t()}
when current_value: value()

Gets the value from key and updates it. Raises if there is no key.

This fun argument receives the value of key and must return a two-element tuple: the current value (the retrieved value, which can be operated on before being returned) and the new value to be stored under key.

The returned value is a tuple with the current value returned by fun and a new keyword list with the updated value under key.

Examples

iex> Keyword.get_and_update!([a: 1], :a, fn current_value ->
...>   {current_value, "new value!"}
...> end)
{1, [a: "new value!"]}

iex> Keyword.get_and_update!([a: 1], :b, fn current_value ->
...>   {current_value, "new value!"}
...> end)
** (KeyError) key :b not found in: [a: 1]

iex> Keyword.get_and_update!([a: 1], :a, fn _ ->
...>   :pop
...> end)
{1, []}