Declaratively control various aspect of HTML fragments:
- Sanitize them
- Bring them from a separate URL (aka "client side include")
- Buffer them instead of stream
Composing different bits of HTML is one of the first things developer reach out for - but the platform doesn't provide it. Instead, people have to turn to bespoke and fragmented server-side solutions, or to bespoke and fragmented JS.
With the added value of control flow (buffering vs. streaming) and sanitization, there is now more to be offered by enabling this kind of capability as a client-side feature.