Class Patch

dash/_patch.py:18–175

Patch a callback output value Act like a proxy of the output prop value on the frontend. Supported prop types: Dictionaries and lists.

class Patch:
    """
    Patch a callback output value

    Act like a proxy of the output prop value on the frontend.

    Supported prop types: Dictionaries and lists.
    """

    def __init__(
        self,
        location: Optional[List[_KeyType]] = None,
        parent: Optional["Patch"] = None,
    ):
        if location is not None:
            self._location: List[_KeyType] = location
        else:
            # pylint: disable=consider-using-ternary
            self._location = (parent and parent._location) or []
        if parent is not None:
            self._operations: List[Dict[str, Any]] = parent._operations
        else:
            self._operations = []

    def __getstate__(self):
        return vars(self)

    def __setstate__(self, state):
        vars(self).update(state)

    def __getitem__(self, item: _KeyType) -> "Patch":
        validate_slice(item)
        return Patch(location=self._location + [item], parent=self)

    def __getattr__(self, item: _KeyType) -> "Patch":
        if item == "tolist":
            # to_json fix
            raise AttributeError
        if item == "_location":
            return self._location  # type: ignore
        if item == "_operations":
            return self._operations  # type: ignore
        return self.__getitem__(item)

    def __setattr__(self, key: _KeyType, value: Any):
        if key in ("_location", "_operations"):
            self.__dict__[str(key)] = value
        else:
            self.__setitem__(key, value)

    def __delattr__(self, item: _KeyType):
        self.__delitem__(item)

    def __setitem__(self, key: _KeyType, value: Any):
        validate_slice(key)
        if value is _noop:
            # The += set themselves.
            return