Allow None in children, but ignore it in output

CHANGELOG.md

@@ -11,6 +11,7 @@
 
 ### Features
 
+* Allow None values through and skip them.
 * Allow primitives through without having to cast them to str first.
 * Add Decimal as an allowed primitive.
 

hypermedia/models/base.py

@@ -101,7 +101,7 @@ def __init__(
         **attributes: Any,
     ) -> None:
         """Initialize Root with children."""
-        self.children = children
+        self.children = tuple(c for c in children if c is not None)
         self.slot = slot
         self.slots = get_slots(self)
         self.attributes = attributes
@@ -117,10 +117,11 @@ def extend(self, slot: str, *children: AnyChildren) -> Self:
             raise ValueError(f"Could not find a slot with name: {slot}")
         element = self.slots[slot]
 
-        element.children = element.children + children
+        new_children = tuple(child for child in children if child is not None)
+        element.children = element.children + new_children
 
         get_child_slots(
-            self.slots, [c for c in children if isinstance(c, Element)]
+            self.slots, [c for c in new_children if isinstance(c, Element)]
         )
         return self
 

hypermedia/types/types.py

@@ -25,7 +25,7 @@ class SafeString(str):
 ComplexChildren: TypeAlias = "Element"
 """Type alias for elements that are allowed to have only non-primitive children."""  # noqa: E501
 
-AnyChildren: TypeAlias = Union[PrimitiveChildren, ComplexChildren]
+AnyChildren: TypeAlias = Union[PrimitiveChildren, ComplexChildren, None]
 """Type alias for elements that are allowed to have any children."""
 
 # PLC0105 `TypeVar` name "TChildren" does not reflect its covariance;

tests/integration/test_formatting.py

@@ -111,3 +111,10 @@ def test_void_elements_and_aliases(
 ) -> None:
     assert element().dump() == result
     assert alias().dump() == result
+
+
+def test_none_children_are_skipped() -> None:
+    assert Bold(None).dump() == "<b></b>"
+    assert Bold("Test", None).dump() == "<b>Test</b>"
+    assert Bold(None, "Test").dump() == "<b>Test</b>"
+    assert Bold(None, None).dump() == "<b></b>"

tests/models/element/test_extend.py

@@ -10,6 +10,23 @@ def test_extend_adds_child_to_slot() -> None:
     assert element.children == (child,)
 
 
+def test_extend_skips_adding_none_child_to_slot() -> None:
+    element = TestElement(slot="my_slot")
+
+    element.extend("my_slot", None)
+
+    assert element.children == ()
+
+
+def test_extend_skips_only_none_values() -> None:
+    element = TestElement(slot="my_slot")
+    child = TestElement()
+
+    element.extend("my_slot", child, None)
+
+    assert element.children == (child,)
+
+
 def test_extend_adds_children_to_slot() -> None:
     element = TestElement(slot="my_slot")
     child_1 = TestElement()

tests/models/element/test_render_children.py

@@ -30,6 +30,7 @@ def test_renders_safe_string_children_as_is() -> None:
 def test_primitive_types_are_rendered() -> None:
     assert TestElement(1)._render_children() == "1"
     assert TestElement(1.1)._render_children() == "1.1"
+    assert TestElement(None)._render_children() == ""
     assert TestElement(True)._render_children() == "True"
     assert TestElement(False)._render_children() == "False"
     assert TestElement("test")._render_children() == "test"