giles 23c88cd1e5 Atomic island hydration: replaceChildren instead of clear+append ...

The hydrate-island function was doing:
  (dom-set-text-content el "")  ;; clears SSR content — visible flash
  (dom-append el body-dom)       ;; adds reactive DOM

Now uses:
  (host-call el "replaceChildren" body-dom)  ;; atomic swap, no empty state

Per DOM spec, replaceChildren is a single synchronous operation — the
browser never renders the intermediate empty state. The MutationObserver
test now checks for content going to zero (visible gap), not mutation
count (mutations are expected during any swap).

Test: "No clobber: clean" — island never goes empty during hydration.
All 8 home features pass: no-flash, no-clobber, boot, islands, stepper,
smoke, no-errors.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

2026-04-10 07:51:37 +00:00

14 KiB

Raw Blame History

View Raw