vmall/openspec/changes/add-mobile-h5/design.md

Design: mobile H5 (add-mobile-h5)

Decision: Nuxt 3 H5 now, Taro deferred

Chosen: a first-party Nuxt 3 H5 app (apps/mobile) reusing @vmall/shared, theme.css, and @vmall/ui.

Considered and deferred: Taro (Vue 3) for H5 + WeChat mini-program from one codebase. Taro is only worth its cost when the mini-program is a committed target: @vmall/ui is DOM-based and does not run in a mini-program, Tailwind needs plugin+rpx workarounds there, createApi needs a transport adapter (fetch does not exist in MP), and MP login needs a wx.login → openid backend endpoint. For H5 alone, Nuxt is strictly better. Deferring Taro later loses little: it would share neither the UI kit nor page code with the Nuxt app anyway.

If the mini-program becomes a target later

Split into three changes instead of one big-bang:

1. add-mobile-taro-scaffold — Taro 4 + Vue 3 workspace app, createApi transport injection (fetch on H5, Taro.request on MP), tab-bar shell, account+password login (works on both, no wx APIs). Acts as the compatibility spike (Taro 4 + pnpm monorepo + CSS variables in WXSS).
2. add-mobile-h5-flows — the page inventory from this change, delivered on the Taro H5 build.
3. add-mobile-miniprogram — MP build target, wx.login session exchange endpoint, share/subscribe messages. Payments can ride the existing wallet (balance payment) to avoid wx.requestPayment merchant onboarding; top-up stays on H5/PC.