fix/263 performance regression (#264)

* Replace deep copies in Component.render
* Add 2nd example component to sampleproject

django_components/component.py

@@ -1,4 +1,3 @@
-import copy
 from typing import (
     TYPE_CHECKING,
     ClassVar,
@@ -126,12 +125,13 @@ class Component(metaclass=SimplifiedInterfaceMediaDefiningClass):
         return self._outer_context or {}
 
     def get_updated_fill_stacks(self, context):
-        current_fill_stacks = context.get(FILLED_SLOTS_CONTEXT_KEY, None)
+        current_fill_stacks: Optional[Dict[str, List[FillNode]]] = context.get(
-        updated_fill_stacks = (
+            FILLED_SLOTS_CONTEXT_KEY, None
-            copy.deepcopy(current_fill_stacks)
-            if current_fill_stacks is not None
-            else {}
         )
+        updated_fill_stacks = {}
+        if current_fill_stacks:
+            for name, fill_nodes in current_fill_stacks.items():
+                updated_fill_stacks[name] = list(fill_nodes)
         for name, fill in self.instance_fills.items():
             if name in updated_fill_stacks:
                 updated_fill_stacks[name].append(fill)

sampleproject/components/calendar/calendar.html

@@ -1 +1,13 @@
-<div class="calendar-component">Today's date is <span>{{ date }}</span></div>
+<div class="calendar-component">
+  <div>Today's date is <span>{{ date }}</span></div>
+  <div>Your to-dos:</div>
+  <ul>
+    <li>
+      {% component_block "todo" %}
+        {% fill "todo_text" %}
+          Stop forgetting the milk!
+        {% endfill %}
+      {% endcomponent_block %}
+    </li>
+  </ul>
+</div>

sampleproject/components/todo/todo.html

@@ -0,0 +1,4 @@
+<div class="todo-item">
+  {% slot "todo_text" %}
+  {% endslot %}
+</div>

sampleproject/components/todo/todo.py

@@ -0,0 +1,9 @@
+from django_components import component
+
+
+@component.register("todo")
+class Calendar(component.Component):
+    # Note that Django will look for templates inside `[your apps]/components` dir and
+    # `[project root]/components` dir. To customize which template to use based on context
+    # you can override def get_template_name() instead of specifying the below variable.
+    template_name = "todo/todo.html"