Method map

returns/future.py:172–198

Applies function to the inner value. Applies 'function' to the contents of the IO instance and returns a new ``Future`` object containing the result. 'function' should accept a single "normal" (non-container) argument and return a non-container result.

(
        self,
        function: Callable[[_ValueType_co], _NewValueType],
    )

        return IO(await self._inner_value)

    def map(
        self,
        function: Callable[[_ValueType_co], _NewValueType],
    ) -> 'Future[_NewValueType]':
        """
        Applies function to the inner value.

        Applies 'function' to the contents of the IO instance
        and returns a new ``Future`` object containing the result.
        'function' should accept a single "normal" (non-container) argument
        and return a non-container result.

        .. code:: python

          >>> import anyio
          >>> from returns.future import Future
          >>> from returns.io import IO

          >>> def mappable(x: int) -> int:
          ...    return x + 1

          >>> assert anyio.run(
          ...     Future.from_value(1).map(mappable).awaitable,
          ... ) == IO(2)

        """
        return Future(_future.async_map(function, self._inner_value))

    def apply(
        self,