Add is_component_type utility (#104)

* feat: add is_component_type utility

* fix typo

* feat: add is_htmy_component_type()

Author: volfpeter

htmy/__init__.py

@@ -1,4 +1,4 @@
-__version__ = "0.10.1"
+__version__ = "0.10.2"
 
 from .core import ContextAware as ContextAware
 from .core import Formatter as Formatter
@@ -38,6 +38,8 @@
 from .utils import as_component_sequence as as_component_sequence
 from .utils import as_component_type as as_component_type
 from .utils import is_component_sequence as is_component_sequence
+from .utils import is_component_type as is_component_type
+from .utils import is_htmy_component_type as is_htmy_component_type
 from .utils import join
 from .utils import join_components as join_components
 

htmy/utils.py

@@ -1,10 +1,12 @@
 from __future__ import annotations
 
 from collections.abc import Generator
-from typing import TYPE_CHECKING, TypeGuard
+from typing import TYPE_CHECKING, Any, TypeGuard
+
+from htmy.typing import ComponentType
 
 if TYPE_CHECKING:
-    from .typing import Component, ComponentSequence, ComponentType
+    from .typing import Component, ComponentSequence, ComponentType, HTMYComponentType
 
 
 def join_components(
@@ -44,13 +46,26 @@ def join(*items: str | None, separator: str = " ") -> str:
     return separator.join(i for i in items if i)
 
 
+def is_htmy_component_type(comp: Any) -> TypeGuard[HTMYComponentType]:
+    """Returns whether the given object is a `HTMYComponentType` (has a `htmy` method)."""
+    # Lazy check, should be good enough.
+    return hasattr(comp, "htmy")
+
+
+def is_component_type(comp: Any) -> TypeGuard[ComponentType]:
+    """Returns whether the given object is a `ComponentType`."""
+    # Lazy check when it comes the htmy components, should be good enough.
+    # No `is_htmy_component_type()` call to avoid trivial extra function call.
+    return comp is None or isinstance(comp, str) or hasattr(comp, "htmy")
+
+
 def is_component_sequence(comp: Component) -> TypeGuard[ComponentSequence]:
-    """Returns whether the given component is a component sequence."""
+    """Returns whether the given component is a `ComponentSequence`."""
     return isinstance(comp, (list, tuple))
 
 
 def as_component_sequence(comp: Component) -> ComponentSequence:
-    """Returns the given component as a component sequence."""
+    """Returns the given component as a `ComponentSequence`."""
     # mypy doesn't understand the `is_component_sequence` type guard.
     return comp if is_component_sequence(comp) else (comp,)  # type: ignore[return-value]