labthings_fastapi.computed_properties
=====================================

.. py:module:: labthings_fastapi.computed_properties

.. autoapi-nested-parse::

   Computed properties.

   A computed property is like a functional property, but it only depends on
   properties which are observable.
   This means LabThings is able to recompute
   it whenever its dependencies change, allowing it to be observed.



Functions
---------

.. autoapisummary::

   labthings_fastapi.computed_properties.computed_property


Module Contents
---------------

.. py:function:: computed_property(fget: collections.abc.Callable[[labthings_fastapi.properties.Owner], labthings_fastapi.properties.Value]) -> ComputedProperty[labthings_fastapi.properties.Owner, labthings_fastapi.properties.Value]

   Decorate a method as a computed property.

   Computed properties are simple functional properties that only depend on other
   properties of their host Thing. Unlike functional properties, it's possible to
   observe them for changes, and LabThings will recalculate them automatically when
   their dependencies change.

   See :ref:`computed_properties` for full details of how computed properties work and
   how to use them.

   :param fget: the getter function, which must depend only on observable properties.
   :return: a computed property descriptor.