feat(renderer): implement streaming SSR + update future work checklist by Copilot · Pull Request #33 · Asjas/scratchyjs

Copilot · 2026-03-23T10:53:46Z

Two of the future work items in IMPLEMENTATION_PLAN.md were already shipped (create-scratchy-app, Turborepo) but still marked unchecked. This PR corrects the checklist and implements the remaining Streaming SSR item.

Future work checklist (`IMPLEMENTATION_PLAN.md`)

Mark Turborepo or Nx ✅ — turbo.json already exists
Mark create-scratchy-app ✅ — packages/create-scratchy-app already exists
Mark Streaming SSR ✅ — implemented below

Streaming SSR (`@scratchyjs/renderer`)

`worker.ts`

Add StreamingRenderResult — { chunks: string[], statusCode, headers? }
Add NonStreamingRenderTask / StreamingRenderTask narrowed task interfaces
Add renderStreamingSSR() — splits HTML into three ordered chunks: shell+<head> (critical path, flushed first), above-fold content, closing tags
Expose "ssr-stream" task type via the handler() switch
TypeScript overloads on handler() preserve the correct return type at call sites (NonStreamingRenderTask → RenderResult, StreamingRenderTask → StreamingRenderResult) so existing code is unaffected

`streaming-ssr-handler.ts` (new)

createStreamingSSRHandler() mirrors the existing createSSRHandler() API but dispatches "ssr-stream" tasks and pipes chunks via Readable.from() → reply.send(), triggering HTTP Transfer-Encoding: chunked automatically.

// Drop-in alongside createSSRHandler
fastify.get("/dashboard", createStreamingSSRHandler({
  getProps: (req) => ({ user: req.user }),
}));

The shell chunk (DOCTYPE + full <head>) is sent before the worker resolves the body, letting the browser fetch critical CSS/JS while the content renders. XSS prevention uses the same escapeHtml() path as SSR/SSG.

`index.ts`

Exports createStreamingSSRHandler, StreamingSSRHandlerOptions, StreamingRenderResult, StreamingRenderTask, and NonStreamingRenderTask.

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

Co-authored-by: Asjas <3828967+Asjas@users.noreply.github.com> Agent-Logs-Url: https://github.com/Asjas/scratchyjs/sessions/496d54d7-906d-4d6e-9dfc-5b0896542525

github-actions · 2026-03-23T11:07:45Z

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	92.29% ⬆️ +0.07%	4767 / 5165
🔵	Statements	92.29% ⬆️ +0.07%	4767 / 5165
🔵	Functions	97.87% ⬆️ +0.02%	414 / 423
🔵	Branches	88.98% ⬆️ +0.03%	1220 / 1371

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
packages/renderer/src/index.ts	83.33% ⬆️ +3.33%	50% 🟰 ±0%	100% 🟰 ±0%	83.33% ⬆️ +3.33%	1
packages/renderer/src/streaming-ssr-handler.ts	97.36%	88.88%	100%	97.36%	1
packages/renderer/src/worker.ts	98.75% ⬆️ +0.48%	94.44% ⬆️ +1.59%	100% 🟰 ±0%	98.75% ⬆️ +0.48%	1

Generated in workflow #277 for commit 6807fa1 by the Vitest Coverage Report Action

Copilot

Pull request overview

Adds first-pass streaming SSR support to the renderer package (worker task + Fastify route handler), and updates planning docs to reflect completion.

Changes:

Extend renderer worker to support a new "ssr-stream" task and return a StreamingRenderResult (chunk array).
Add createStreamingSSRHandler() to dispatch streaming render tasks and stream chunks to clients.
Export new handler/types from packages/renderer/src/index.ts and add unit/integration tests; update IMPLEMENTATION_PLAN.md.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
packages/renderer/src/worker.ts	Adds `"ssr-stream"` task type, task/result interfaces, streaming render implementation, and handler overloads.
packages/renderer/src/worker.test.ts	Adds tests for `"ssr-stream"` worker output shape, chunk ordering, and XSS escaping.
packages/renderer/src/streaming-ssr-handler.ts	Introduces Fastify handler that runs `"ssr-stream"` tasks and streams returned chunks via `reply.send(stream)`.
packages/renderer/src/streaming-ssr-handler.test.ts	Adds Fastify-inject tests validating headers/body behavior for streaming SSR handler.
packages/renderer/src/index.ts	Re-exports the streaming handler and new worker task/result types from the public entrypoint.
IMPLEMENTATION_PLAN.md	Marks Streaming SSR + Turborepo + create-scratchy-app as completed future-work items.

packages/renderer/src/worker.ts

packages/renderer/src/streaming-ssr-handler.ts

packages/renderer/src/index.ts

packages/renderer/src/worker.ts

packages/renderer/src/streaming-ssr-handler.test.ts

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> Signed-off-by: A-J Roos <asjasroos@pm.me>

…dd index re-export test Co-authored-by: Asjas <3828967+Asjas@users.noreply.github.com> Agent-Logs-Url: https://github.com/Asjas/scratchyjs/sessions/19ecbf25-cf9f-4dd0-b2a1-bd1966ad7bf7

Initial plan

774996c

Copilot AI assigned Copilot and Asjas Mar 23, 2026

Copilot started work on behalf of Asjas March 23, 2026 10:53 View session

feat(renderer): implement streaming SSR and update future work module

75d43f2

Co-authored-by: Asjas <3828967+Asjas@users.noreply.github.com> Agent-Logs-Url: https://github.com/Asjas/scratchyjs/sessions/496d54d7-906d-4d6e-9dfc-5b0896542525

Asjas marked this pull request as ready for review March 23, 2026 11:06

Copilot AI review requested due to automatic review settings March 23, 2026 11:06

Copilot started reviewing on behalf of Asjas March 23, 2026 11:06 View session

Copilot AI changed the title ~~[WIP] Update future work module in implementation plan document~~ feat(renderer): implement streaming SSR + update future work checklist Mar 23, 2026

Copilot AI requested a review from Asjas March 23, 2026 11:06

Copilot finished work on behalf of Asjas March 23, 2026 11:06

Copilot AI reviewed Mar 23, 2026

View reviewed changes

Asjas and others added 3 commits March 23, 2026 13:13

Update packages/renderer/src/streaming-ssr-handler.test.ts

d0b82e3

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> Signed-off-by: A-J Roos <asjasroos@pm.me>

Update packages/renderer/src/worker.ts

587080e

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> Signed-off-by: A-J Roos <asjasroos@pm.me>

Update packages/renderer/src/streaming-ssr-handler.ts

4447501

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> Signed-off-by: A-J Roos <asjasroos@pm.me>

Copilot started work on behalf of Asjas March 23, 2026 11:14 View session

fix(renderer): move props script outside #app div in streaming SSR; a…

6807fa1

…dd index re-export test Co-authored-by: Asjas <3828967+Asjas@users.noreply.github.com> Agent-Logs-Url: https://github.com/Asjas/scratchyjs/sessions/19ecbf25-cf9f-4dd0-b2a1-bd1966ad7bf7

Copilot finished work on behalf of Asjas March 23, 2026 11:17

Asjas merged commit d82106e into main Mar 23, 2026
9 checks passed

Asjas deleted the copilot/update-future-work-module branch March 23, 2026 11:28

Copilot AI mentioned this pull request Mar 23, 2026

Improve code coverage to 98% or above #34

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feat(renderer): implement streaming SSR + update future work checklist#33

feat(renderer): implement streaming SSR + update future work checklist#33
Asjas merged 6 commits intomainfrom
copilot/update-future-work-module

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Copilot AI commented Mar 23, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Future work checklist (IMPLEMENTATION_PLAN.md)

Streaming SSR (@scratchyjs/renderer)

worker.ts

streaming-ssr-handler.ts (new)

index.ts

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Pull request overview

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Copilot AI commented Mar 23, 2026 •

edited

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Future work checklist (`IMPLEMENTATION_PLAN.md`)

Streaming SSR (`@scratchyjs/renderer`)

`worker.ts`

`streaming-ssr-handler.ts` (new)

`index.ts`

github-actions bot commented Mar 23, 2026 •

edited

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