Observe-only

An observe-only Area returns None from tick(). Its first tick establishes an ObserveRange without creating an EffectRange.

ObserverArea

ObserverArea keeps the latest snapshot received through the inherited observe() method. Its custom get_snapshot() method gives the caller a copy of the observed sequence.

from hydrangea.context import NativeContent
from hydrangea.context.area import Area, AreaInvokeTiming


class ObserverArea(Area):
    def __init__(self) -> None:
        super().__init__(invoke_timing=AreaInvokeTiming.deferrable)

    def tick(self) -> None:
        return None

    def get_snapshot(self) -> list[NativeContent]:
        return list(self._observe_snapshot)

P.S. This is a shallow copy. The provider-native elements remain shared and should be treated as read-only. To modify an element, explicitly create an independent copy of it first, including any nested data you intend to change.