Move SSE out of htmx core into a standalone extension (hx-sse.js).
The new extension uses Fetch + ReadableStream instead of EventSource,
so it works with POST, custom headers, and cookies. Two modes:
- One-off streams: any hx-get/hx-post returning text/event-stream
- Persistent connections: hx-sse:connect with auto-reconnect
SSE events now follow the extension pattern:
- htmx:before:sse:connection / htmx:after:sse:connection
- htmx:before:sse:message / htmx:after:sse:message
- htmx:sse:error / htmx:sse:close
New features:
- hx-sse:close="eventname" to close connection on a named event
- htmx:sse:close event with reason (message, removed, ended, etc.)
- htmx:before:response core event for extension response interception
- Server retry: field updates reconnect delay per SSE spec
- Non-2xx reconnect responses fire htmx:sse:error
SSE parser improvements (spec compliance):
- Handle CRLF, CR, and LF line endings
- Strip leading BOM (U+FEFF)
- Dispatch empty data fields
- Ignore id fields containing NULL
- Process field-only lines (no colon) per spec
Docs:
- Document htmx:before:response in events, reference, building guide
- Add htmx 2.x → 4.x SSE migration guide
- Document hx-sse:close and htmx:sse:close
- Add hx-sse:connect, hx-sse:close to JetBrains web-types
- Fix stale Accept header reference in migration guide
Remove htmx.config.sse from core config tables (extension-only now).
Remove stale SSE event references from core docs.
* remove apline attributes from pre settle nodes
* simplify a little
* move to an extension
* Try applying alpine to fragments before swap
* handle morph properly
* defer count tracking
* handle child template morph and use local alpine for test reliablilty
* improve defercount
* post rebase tidy
* improve x-id and x-for handling
* patch isSoftMatch instead of removing generated id's
