[dave-hillier]

Closes the September deep review: all 38 issues (#143–#180), plus #181, which was filed while this work was in progress.

Nothing was pushed while the work was done, so this is the first reviewable view of it. It is one branch because the fixes share a small number of hot files (notably src/react/Replot.tsx and src/react/useMark.ts, which 14 issues converge on), and parallel work would only have produced conflicts.

The branch now contains origin/main, so the 0.1.0-alpha.1 packaging work is merged in and this PR merges as a fast-forward.

By area

Pointer interaction (#143, #144). The selection store reports the clearing value when the mark showing a tip unmounts, instead of holding the vanished datum and swallowing the next selection of it. The removed usePointer exports are documented as breaking.

Marks (#156–#166). AreaY line draws a topline; custom marker functions draw, with defs scoped to the mark that uses them; a channel-driven <title> is a child of the element it describes; difference composes its render onto the areas and stops churning clip ids; raster parses colours through the canvas once instead of per pixel and honours colorSpace; zero-valued rotate and zero-length vectors are emitted rather than silently dropped.

Tips (#159–#162, #178). The box is measured and the anchor flips to fit the frame; per-datum channel styles no longer tint it, which is what had put two plots on the parity allow list for the wrong reason; a format returning null no longer throws on hover.

React core (#145, #146, #148–#151). Marks and scales register from layout effects, so StrictMode and registration order are correct by construction rather than by accident; computePlot failures reach an enclosing error boundary; an unserialisable prop no longer keys a plot at random; an accessor that closes over React state recomputes the plot.

Rendering (#152, #153, #168, #177, #180). No direct DOM manipulation from React, and svg.scale is the lookup function the imperative API exposes rather than the raw scales object; the svg shell is shared between the React and static paths; warnings drain after the marks render, so a render-time warning belongs to the plot that raised it; a faceted mark announces itself once rather than once per facet.

Server rendering (#147). renderToString returns the whole plot instead of an empty host. A hydrating client redraws it, because marks register from an effect, and README and the docs now say that rather than claiming SSR works unchanged.

Packaging (#154, #174, #175). The replot/react entry moved out of index.tsx; the main, module and umd conditions and the bundle filename are fixed; react and react-dom are required peers, as plot() and legend() statically import react-dom/server; a pack-and-install smoke test now imports both entry points through a bundler, TypeScript and the UMD bundle as part of yarn test.

Parity and tests (#169–#171). The parity comparison now runs in CI against a pinned upstream checkout, and parity-allow.json records each plot's expected divergence as a machine-checked signature rather than a bare name, so a listed plot that diverges further fails the build. StrictMode coverage and the null-data assertions were replaced with ones that can actually fail.

Docs and tooling (#172, #173, #179). The inherited Observable Plot changelogs, images and docs twins are gone; coverage measures the TypeScript sources; the React hooks rules are enabled.

Reconciling with origin/main

Merging the release line in hit 15 real conflicts, and three of them were disagreements rather than overlaps. The merge commit records each decision:

• Packaging takes the base's: package name @dave-hillier/replot, the compiled dist/esm build, its entry points and its release workflow, with this branch's entry rename applied on top.
• Source layout takes this branch's: plot() stays in plot.ts with the rest of the fixes rather than moving back to the base's plotDom.ts split.
• renderTransform.ts keeps the base's jsxToDom (it builds DOM directly rather than importing react-dom/server, the fix for Published package breaks the Vite dev server: CJS deps reach the browser unconverted #140) with this branch's userRenderOf restored — without it, a transform composed under pointer() never ran.
• Legend.tsx keeps the base's LegendProps union and resolveLegendElement (LegendProps is missing the plot-scoped scale prop, so <Legend scale="color"> fails to typecheck #136) with this branch's render-phase registration, since effect-based registration never runs on a server.
• One trap worth naming: src/react/api.d.ts was a hand-written re-export that the entry rename turned into a self-reference, and it overwrote the generated declaration in dist, so a TypeScript consumer saw no exports from replot/react. It is deleted.

Verification

yarn test            1818 passing, 2 pending, 0 failing; tsc, lint and prettier clean
yarn test:smoke      all four checks pass against the dist entry points
yarn test:package    publint clean; arethetypeswrong green on node16 ESM, bundler, node10 and node16 CJS
yarn parity --fail   219 of 219 allow-list entries match, 0 problems
yarn docs:build      succeeds

One CI finding

The Node matrix this work added turned up a snapshot that is not byte-stable across V8 lines. projectionDomainRatioNC renders the same polygon from a different starting vertex on Node 24 than on Node 22, because d3-geo's clipping is sensitive to the floating-point behaviour of the V8 the tests run on; the geometry is identical, only the ring's start moves. Reproduced locally on 24.21.0, byte-identical to what CI produced, and it is the only plot affected.

The snapshots are therefore checked on the primary line only, and the other lines run every test except the snapshot harness, so a Node-specific breakage in the library still shows up.

🤖 Generated with Claude Code