mirror of
https://github.com/heygen-com/hyperframes.git
synced 2026-09-03 04:38:33 +00:00
Vance Ingalls
150d9348bc
## Summary
Adds `srcdoc` support to `<hyperframes-player>` and uses it from studio's `Player.tsx` so composition switches no longer trigger an iframe navigation. Studio fetches the composition HTML on the parent and hands it to the iframe inline; the browser skips the navigation request, preconnect/handshake, and a redundant cache lookup.
## Why
Step `P3-2` of the player perf proposal. Profiling studio's project switcher showed that ~30–80 ms of every composition swap was spent in the iframe's own navigation pipeline — DNS / TCP / TLS reuse checks, request hand-off to the network process, and the second cache lookup against the same origin we just fetched from. For same-origin previews (`/api/projects/.../preview`) this is pure overhead: the parent already has the bytes (or can pull them from its own HTTP cache).
`srcdoc` lets us skip that pipeline entirely. The iframe loads from an in-memory string and the parent's `fetch` reuses any existing response from the page's HTTP cache, so the second-and-Nth composition switch in a session is essentially free at the network layer.
## What changed
### `<hyperframes-player>` (`packages/player/src/hyperframes-player.ts`)
- Added `srcdoc` to `observedAttributes` so runtime swaps actually fire `attributeChangedCallback`.
- On connect, both `srcdoc` and `src` are forwarded to the inner iframe — no manual precedence; the HTML spec already says `srcdoc` wins when both are present, so the browser handles arbitration.
- New `srcdoc` branch in `attributeChangedCallback`:
- Resets `_ready = false` on every change so the next iframe `load` event re-runs probe/control/poster setup against the fresh document.
- Distinguishes `setAttribute("srcdoc", "")` (deliberate empty document) from `removeAttribute("srcdoc")` (fall back to `src`) — the former propagates an empty-string srcdoc; the latter strips the attribute so a previously-set `src` can take over.
### Studio `Player.tsx` (`packages/studio/src/player/components/Player.tsx`)
- Hoisted `AbortController` and resolved `url` outside the dynamic-import `.then()` so the cleanup function can cancel an in-flight composition fetch when the user navigates away mid-load.
- After the player module loads, `fetch(url, { signal })` pulls the composition HTML on the parent.
- Success → `player.setAttribute("srcdoc", html)`.
- Network error / non-2xx → fall back to `player.setAttribute("src", url)`. Same code path the player has always taken, so this optimization is strictly a win — never a regression.
- `AbortError` → bail without touching the DOM (component is unmounting).
- Attributes are set **before** `appendChild` so the iframe never loads an intermediate `about:blank`. That matters because:
1. The first iframe `load` event must fire for the real composition; the existing handler treats `loadCountRef > 1` as a hot-reload and replays the reveal animation. An extra `about:blank` load would trigger the reveal on initial mount.
2. `useTimelinePlayer` hangs setup off the first load — running it against an empty document is wasted work.
## Test plan
- [x] 7 new unit tests in `hyperframes-player.test.ts` covering:
- `srcdoc` is in `observedAttributes`.
- Initial `srcdoc` set before connect forwards to the iframe on connect.
- Runtime `srcdoc` set after connect forwards via `attributeChangedCallback`.
- `_ready` resets when `srcdoc` changes so `onIframeLoad` replays setup.
- `removeAttribute("srcdoc")` strips the attribute on the iframe so `src` can take over.
- Empty-string `srcdoc` is preserved (not treated as removal).
- Both `src` and `srcdoc` set together: both get forwarded to the iframe and the browser arbitrates per spec.
- [x] Studio fallback path verified manually — disabling fetch falls back to the original `src` flow with no regression.
## Stack
Step `P3-2` of the player perf proposal. Builds on `P3-1` (sync seek) — both target the studio editor's interactive feel. With sync seek removing scrub latency and `srcdoc` removing composition-switch latency, the editor's two most-frequent interactions both shed their iframe-navigation overhead.