port-html-to-react

Context

• HTML reference repo: https://github.com/digital-go-jp/design-system-example-components-html
• Target directory pattern: src/components/<Name>/
• Read component-rules first. This skill assumes its rules (component design, file layout, styling, accessibility, Storybook conventions, testing) and only adds the port-specific flow on top.

Steps

1. Read the spec and the codebase

   • Fetch the component's reference files from the HTML repo. Use curl via Bash, not WebFetch — WebFetch summarizes content past a quote limit and will silently truncate the spec/markup/CSS. Example:

     mkdir -p /tmp/<component>-html && cd /tmp/<component>-html
     for f in <component>.mdx <component>.html <component>.css <component>.js <component>.stories.ts <component>.test.js <component>.vrt.js <component>.unit.js; do
       curl -sSL "https://raw.githubusercontent.com/digital-go-jp/design-system-example-components-html/main/src/components/<component>/$f" -o "$f"
     done

     Then read the files locally. Test file roles in the HTML reference:

     • <component>.test.js — behavior tests (interaction, ARIA wiring, etc.)
     • <component>.vrt.js — visual regression tests for the reset-CSS variant
     • <component>.unit.js — jsdom-based unit tests for any logic split out of the component

     Not every component has all three. A 404 from curl just means that file doesn't exist; ignore it and move on.

   • Run through component-rules § Before writing code — read a similar existing component's full file set to pick up patterns before writing anything.
2. Read the HTML reference implementation
   • Markup and styles. The HTML reference uses plain CSS with BEM-style class names (dads-<name>, dads-<name>__<part>) in a sibling <component>.css — not Tailwind. Translate those rules into Tailwind utility classes (with theme-plugin tokens) on the React side; don't carry the BEM class names over.
   • Read the companion Custom Element JS (e.g. progress-indicator.js) carefully. Behavior is not inline in the HTML — it lives in a class Foo extends HTMLElement / customElements.define('dads-foo', Foo) file. That file is where you'll find:
     • Attribute reactions (observedAttributes, attributeChangedCallback) — what state changes the component responds to.
     • Lifecycle work (connectedCallback / disconnectedCallback) — ARIA wiring (role, aria-valuenow, aria-labelledby), live-region announcers, timers/intervals, validation.
     • Public properties / methods (get value(), start(), stop(), etc.) — the imperative API consumers use.
     • [data-js-*] selectors — these are JS-only hooks for querySelector. The React port doesn't need them; express the same wiring through component structure / props instead.
   • The React port has to reproduce this behavior without useState / useEffect / useRef in the component body (see component-rules § No logic in the component body). Plan where each piece goes: Story-side demo state, a separate hook file (useFooAnnouncer.ts etc.), or pure data-* + CSS.
   • Note prefers-reduced-motion: reduce and forced-colors handling — mirror them as-is.
   • @media (hover: hover) does not need to be ported. The HTML reference wraps hover styles in @media (hover: hover) to prevent sticky-hover on touch devices, but Tailwind's hover: variant is the accepted equivalent in this project. Use plain hover: utilities.
   • Don't port the reset CSS that the HTML reference uses to normalize elements — Preflight already covers it. See component-rules § Don't re-implement Preflight.

3. Write a port plan and get user approval before coding — required.

   • After Steps 1–2, write src/components/<Name>/component-spec.md (template at the end of this file). Cover at minimum:
     • Component design: which sub-components / props / data-* attributes you'll expose, how children compose, what is intentionally not in the component API (e.g. placeholder icons — see below).
     • File layout: which files you'll create. Default to one <Name>.tsx with Tailwind classes inline in the JSX; only propose types.ts / a hook file when the complexity actually warrants it (see component-rules § File layout).
     • Story plan: which Stories to mirror from the HTML version (one per HTML file, plus Playground).
     • Test plan: whether tests are needed, with reasoning, and the target cases if any. Decision rule: write-tests.
     • Intentional deviations from the HTML reference: anything you plan to do differently from the HTML version (and why).
   • Present the plan to the user and wait for confirmation before writing component code. The plan exists so the user can redirect file layout, prop shape, and Story/test scope before code is written, not after.
   • Commit component-spec.md to the repo as a deliverable. It's not a throwaway working doc — it's the artifact reviewers use to evaluate the port on the PR. Commit it as part of the port (typically the first commit on the branch, before the implementation), and keep it in sync if the design changes during implementation. Don't leave it untracked or add it as an after-the-fact follow-up commit.

   Defaults to bake into the plan:

   • Start with everything in <Name>.tsx. Do not split files preemptively.
   • Don't componentize placeholder icons. When the HTML reference shows decorative or example SVGs at icon slots (front/tail/end icons, illustrative glyphs in demos), do not create wrapper components like <FooFrontIcon> for them. Consumers bring their own icons of unknown shape/size, so the component can't usefully fix width/viewBox/fill. Instead, the component contributes only the layout / behavior classes via the slot's container, and the Story renders raw <svg> elements with the required slot classes attached directly. Document the required classes for each slot in the <Name>.mdx docs page so consumers know what to attach.
   • Don't create pass-through wrapper components. If an HTML reference element only carries a BEM class for styling (e.g. <span class="dads-menu-list__label">) and that class is replaced by Tailwind utilities in the React port, the wrapper has nothing left to do. Don't expose it as a sub-component (<MenuListItemLabel>) — apply the Tailwind classes directly on the parent's children, or have consumers pass the inner content as a prop / children. A wrapper is only justified when it owns layout / data-* / behavior that consumers can't sensibly attach themselves.
4. Implement the React component (only after the user approves the plan from Step 3)
   • Follow the rules in component-rules (composition, native-prop extension, no logic in body, no cross-component imports, no shared config additions, styling tokens, data-* + group-data-[...] pattern).
   • Reproduce HTML markup, classes, and behavior as-is. Do not introduce improvements.
5. Build the Storybook entries
   • Follow component-rules § Storybook conventions for the basics (Playground Story, export-name → HTML-file-name mapping).
   • Mirror the HTML Storybook layout: one Story per HTML file. Story export names (and the name field when set) stay in English — only user-visible UI copy (button labels, captions, etc.) is in Japanese.
   • Author the <Name>.mdx docs file following the write-component-docs skill.
   • Register the component in .storybook/preview.ts story sort order, in Japanese 50音順 (gojūon). The list under parameters.options.storySort.order > 'Component' is ordered by each title's kana reading — insert the new title at the right position (e.g. ボタン falls after プログレスインジケーター (ぷ) and before 見出し (み), not next to パンくずナビゲーション). Re-read the surrounding entries to confirm placement.
   • Add the component to src/index.ts with export * from './components/<Name>';, keeping the list alphabetized.
6. Tests
   • Decide whether tests are needed, and follow the conventions for writing them, per write-tests (see § When to skip tests entirely for the skip rule).
7. Run the pre-completion checklist
   • Invoke the pre-completion-check skill.
   • Manually verify each Story in Storybook against the HTML reference side-by-side.

Naming reminders

• Branch: feature/<component-name> (lowercase, hyphenated).
• Commit scope: component PascalCase, e.g. feat(ProgressIndicator): ....
• UI copy: Japanese. Code, types, comments, Story export names, Story name fields: English.

Checklist

This checklist covers only the port-specific items. The general rules in component-rules (component design, styling, accessibility, Storybook conventions, testing, code style) apply on top — verify against that skill as well, do not assume.

Plan

• src/components/<Name>/component-spec.md was written after Steps 1–2 and approved by the user before any component code was written.
• component-spec.md is committed to the branch (typically the first commit, before the implementation), not left untracked or added as a follow-up.
• The implementation matches the approved plan, or any deviation has been re-confirmed with the user and reflected back into component-spec.md.

HTML reference parity

• Markup matches the HTML reference (element names, structure, ARIA attributes).
• Behavior matches the HTML reference. No "improvements" introduced during the port.
• No wrapper components were created for placeholder icons; the Story renders raw <svg> with the slot classes documented in the <Name>.mdx docs page.
• No pass-through wrapper components were created for HTML elements that only carried a BEM class (and whose Tailwind classes can sit on the parent or on children).
• Reset CSS from the HTML reference was not ported (Preflight covers it — see component-rules § Don't re-implement Preflight).
• prefers-reduced-motion: reduce and forced-colors handling mirror the HTML reference.
• Reference repo SHA / path noted somewhere (commit message, PR description, or component-spec.md if used).

Storybook & registration

• Every HTML file has a matching Story; export name matches the HTML file name (spinner-loop.html → SpinnerLoop).
• The component's Japanese title is added to .storybook/preview.ts story sort order in 50音順.
• src/index.ts re-exports the new component (export * from './components/<Name>';), kept alphabetized.

Tests

• Followed write-tests, including its § When to skip tests entirely rule.

Pre-completion

• Run the pre-completion-check skill (lint / markup lint / build / test).
• Visually verify each Story side-by-side with the HTML reference in Storybook.

component-spec.md template (port plan)

Write this at src/components/<Name>/component-spec.md after Steps 1–2 and before writing any component code. The point is to surface design decisions early so the user can redirect them. Keep it brief — bullets, not prose. component-spec.md is a required, committed deliverable (see Step 3) — commit it as part of the port (typically the first commit, before the implementation) and keep it in sync when the design changes during implementation.

# <Component> 移植計画

## HTML reference

- Source: https://github.com/digital-go-jp/design-system-example-components-html/tree/<sha-or-branch>/<path>
- 関連ファイル:
  - `<component>.mdx` / `<component>.html` / `<component>.css` / `<component>.js`
  - `<component>.stories.ts` (Storybook)
  - `<component>.test.js`（機能テスト） / `<component>.vrt.js`（リセット CSS VRT） / `<component>.unit.js`（jsdom ユニット） — 存在するもの

## コンポーネント設計

- 公開する構成要素（例: `Foo`, `FooItem`, `FooLabel`）
- 各要素の props（型・必須/任意・デフォルト）
- ルートで持たせる `data-*` 属性とその役割
- 子要素が反応する `group-data-[...]/name` の対応関係
- コンポーネント API に**入れない**もの（プレースホルダーアイコン、アニメーション一時停止、その他）

## ファイル構成

- `<Name>.tsx`（基本これ1つ。Tailwind クラスは JSX に直書き）
- 分割が必要なら理由とともに（`types.ts` / `useFooXxx.ts` / `<Name>.css`）

## Story 構成

- HTML 版にある Story 一覧 → React 版の export 名と表示名
- 追加で必要な Story（`Playground` など）
- `<Name>.mdx` に載せる項目（仕様表、必要クラス一覧など）

## テスト方針

- テストを書く / 書かない、と理由
- 書く場合は対象ケース（focus、keyboard、event payload など）

## HTML 版との意図的な差異

- 何を / なぜ