originalanimal.elm

{-! If there is an original animal to work with, partially apply the
    given function to that animal. The given function is expected to
    transform some value with that function. If there is no animal,
    `identity` is used.

    Typically used to make transformations of Model that mean nothing
    if there's no original animal. (Very likely an "impossible" case.)

    model |> Form.givenOriginalAnimal form upsertAnimal |> noCmd
-}             
givenOriginalAnimal : Form -> (Animal -> anything -> anything)
                    -> (anything -> anything)
givenOriginalAnimal form f  =
  case form.originalAnimal of
    Nothing -> identity
    Just animal -> f animal