WORK-433
ID:WORK-433Status:ready

reveal IntersectionObserver behaviour + enhancement gating

SPEC-105 §5–§6: the timing trigger and the no-JS/SSR safety. A tiny IntersectionObserver behaviour flips data-in-view; enhancement gating guarantees the static page is always complete. JS = when, CSS = how.

Priority:highComplexity:moderateMilestone:v0.23.0Source:SPEC-105
claude/defer-work-417 View source

Criteria completion

Criteria completion: 0 of 3 (0%) checked; tracking started on Jun 15, no incremental history yet0%25%50%75%100%Jun 15Jun 15

Tracking started Jun 15 — check back for trends.

Relationships

Implements 1
Related 5
Branches 4
claude/defer-work-417 current ready
claude/milestone-v0.24.0-split readychangeset-release/main readymain readyclaude/v023-bg-motion-breakdown ready
History 1
  1. b2894b9
    Created (ready)by bjornolofandersson

Scope

  • reveal behaviour — joins tabs/accordion/datatable/form in packages/behaviors/src/. Observes each [data-reveal]:not([data-reveal="none"]) container; on first intersection it sets data-in-view and unobserves. Theme-agnostic: one state attribute, nothing else.
  • Reduced-motion path — honour matchMedia('(prefers-reduced-motion: reduce)'): mark everything in-view immediately (belt-and-braces with the global reset).
  • Enhancement gating (cardinal rule) — SSR/no-JS/crawler render the fully visible final state; never bake opacity:0 that only JS removes. The pre-entrance state is scoped under a root data-animate flag the behaviour adds on boot; no flag → every section fully rendered.

Acceptance Criteria

  • An IntersectionObserver reveal behaviour sets data-in-view on first intersection and unobserves; under prefers-reduced-motion it marks all in-view immediately.
  • Enhancement gating: SSR/no-JS/crawler render the fully visible final state (no opacity:0 baked in); the pre-entrance state is scoped under a root data-animate flag the behaviour adds on boot; the WORK-352 reduced-motion reset still neutralises motion.
  • The behaviour is theme-agnostic (sets only data-in-view/the root flag) and frame-agnostic; tests cover the observe→reveal→unobserve cycle, the reduced-motion path, and the no-JS/SSR complete-render guarantee.

Dependencies

  • WORK-431 — observes data-reveal. Pairs with WORK-432 (the gated pre-entrance CSS).

References

  • SPEC-105 §5–§6 · packages/behaviors/src/ (tabs/accordion/datatable/form pattern) · reduced-motion baseline WORK-352 (packages/lumina/styles/global.css).