v0.142.0 (2025-10-05)¤

__

Feat¤

• New built-in component ErrorFallback

  Use ErrorFallback to catch errors and display a fallback content instead.

  This is similar to React's ErrorBoundary component.

  Either pass the fallback as a kwarg:

  {% component "error_fallback" fallback="Oops, something went wrong" %}
      {% component "table" / %}
  {% endcomponent %}
  

  Or use the full fallback slot:

  {% component "error_fallback" %}
      {% fill "content" %}
          {% component "table" / %}
      {% endfill %}
      {% fill "fallback" data="data" %}
          <p>Oops, something went wrong</p>
          {% button href="/report-error" %}
              Report error
          {% endbutton %}
      {% endfill %}
  {% endcomponent %}
  

• Wrap the template rendering in Component.on_render() in a lambda function.

  When you wrap the rendering call in a lambda function, and the rendering fails, the error will be yielded back in the (None, Exception) tuple.

  Before:

  class MyTable(Component):
      def on_render(self, context, template):
          try:
              intermediate = template.render(context)
              html, error = yield intermediate
          except Exception as e:
              html, error = None, e
  

  After:

  class MyTable(Component):
      def on_render(self, context, template):
          html, error = yield lambda: template.render(context)
  

• Multiple yields in Component.on_render() - You can now yield multiple times within the same on_render method for complex rendering scenarios.

  class MyTable(Component):
      def on_render(self, context, template):
          # First yield
          with context.push({"mode": "header"}):
              header_html, header_error = yield lambda: template.render(context)
  
          # Second yield
          with context.push({"mode": "body"}):
              body_html, body_error = yield lambda: template.render(context)
  
          # Third yield
          footer_html, footer_error = yield "Footer content"
  
          # Process all results
          if header_error or body_error or footer_error:
              return "Error occurred during rendering"
  
          return f"{header_html}\n{body_html}\n{footer_html}"
  

  Each yield operation is independent and returns its own (html, error) tuple, allowing you to handle each rendering result separately.

Fix¤

• Improve formatting when an exception is raised while rendering components. Error messages with newlines should now be properly formatted.

• Add missing exports for OnComponentRenderedContext, OnSlotRenderedContext, OnTemplateCompiledContext, OnTemplateLoadedContext.

Refactor¤

• Changes to how get_component_url() handles query parameters:

  • True values are now converted to boolean flags (e.g. ?enabled instead of ?enabled=True).
  • False and None values are now filtered out.

  url = get_component_url(
      MyComponent,
      query={"abc": 123, "enabled": True, "debug": False, "none_key": None},
  )
  # /components/ext/view/components/c1ab2c3?abc=123&enabled
  

Docs¤

• New people page to celebrate the contributors and authors!