Twig Components (Symfony)

Use when

• Extracting a repeated piece of Twig into a reusable component.
• Building a component with props, slots, computed logic, or CVA variants.
• Making a component reactive with Live Components (search, counters, forms).

Default workflow

1. Choose the kind: anonymous (template only), class-based #[AsTwigComponent], or #[AsLiveComponent].
2. Declare props as public mutable properties; use mount() for derived values.
3. Expose content injection through blocks (slots) rather than more props.
4. For Live Components, mark writable state with #[LiveProp(writable: true)] and debounce user input.
5. Test the PHP class with InteractsWithTwigComponents.

Guardrails

• Never make public props readonly: they are assigned after instantiation.
• Inject services as private readonly, never as public props.
• Only mark a LiveProp writable when the browser must change it.
• Keep one responsibility per component.