Declarative Partial Updates experiments

declarative partial updates experiments

Experiments with the Declarative Partial Updates API and the Navigation API. As little JS as possible. Chrome 148+ behind chrome://flags/#enable-experimental-web-platform-features.

01. Basic marker placeholder + declarative replacement, zero JS.

02. Streaming fetch into elementstreamHTML() piping a chunked fetch into the DOM.

03. HTMX emulationTiny JS that turns data-target attributes into streamed partial updates.

04. Navigation API + DPUSPA routing via navigation.intercept(), content via streamHTML.

05. Islands architectureIndependent islands, each fetched in parallel via DPU.

06. Server-side renderedServer streams the whole document with out-of-order fills.

07. Streaming clockLong-lived response that re-flushes a every second. Zero JS.

08. Skeleton cardPlaceholder shapes that match the final layout — no layout shift on fill.

references

Chrome blog: Declarative Partial Updates — Barry Pollard's introduction to the API.

WICG/declarative-partial-updates — Specification repo with explainers and issues.

Patching explainer — / markers and .

Dynamic-markup explainer — The new streamHTMLUnsafe() / append / prepend / replace methods.

Chrome Status: Out of order streaming — DevTrial in 148 (behind flag), shipping target 150.

Chrome Status: Parse processing instructions in HTML — Supporting work that makes / parseable.

Chrome Status: setHTMLUnsafe and parseHTMLUnsafe — Chrome 124 foundation that the streaming methods extend.

WHATWG HTML PR #11818 — The actual spec change for out-of-order streaming.

WHATWG HTML issue #2142 — The original 2017 thread that led here.

Mozilla standards-positions #1369 — Currently "No signal".

WebKit standards-positions #628 — Currently "Support".

template-for polyfill

html-setters polyfill

Chrome docs: Navigation API

Jason Miller: Islands Architecture

photo-album-server.js — A larger out-of-order streaming demo from the same team.