When used in a struct module, automatically generates a method to determine whether an object is of that type.

Instead of writing:

assert Enum.all?(people, fn
  %Person{} -> true
  _ -> false
end)

IsType will let you write cleaner code:

defmodule Person do
  use IsType

  defstruct id: nil, first_name: nil, last_name: nil
end

assert Enum.all?(people, &Person.is_person?/1)

or if you don't like the default name, specify your own with an atom.

defmodule Person do
  use IsType, function_name: :is_employee

  defstruct id: nil, first_name: nil, last_name: nil
end

assert Enum.all?(people, &Person.is_employee/1)