Slate Browser First Tranche Plan

Goal

Build the first working slate-browser package tranche in .tmp/slate-v2:

• Bun for core fast tests
• Vitest browser for small DOM/browser contract tests
• Playwright helpers for example/e2e tests

First Tranche Shape

1. self-contained package under packages/slate-browser
2. one Bun unit test with global describe / it
3. one Vitest browser contract test
4. one Playwright helper module plus one tiny example integration test
5. one Chromium-only CDP IME helper plus one placeholder-example IME test

Success Criteria

• all three lanes run in this same turn
• the API shape matches the docs enough to validate direction
• the setup reveals whether any early tool/runtime issue should force a pivot

Progress Log

2026-04-03

• created the first package tranche at: /Users/zbeyens/git/slate-v2/packages/slate-browser
• implemented:
  • Bun fast lane with global test API
  • Vitest browser lane with Playwright provider
  • shared Playwright helper module in Slate proper
  • one tiny example integration test using the shared helper API
  • one Chromium CDP IME helper and one placeholder-example IME test
• added root scripts:
  • test:slate-browser
  • test:slate-browser:core
  • test:slate-browser:dom
  • test:slate-browser:e2e
  • test:slate-browser:ime
  • local fixed-port variants for the two Playwright lanes
• early issues found and fixed:
  • Bun runtime globals needed TypeScript support via bun-types/test-globals
  • the helper API had to respect PLAYWRIGHT_BASE_URL
  • repo Playwright needed yarn exec playwright install chromium, not ad hoc npx playwright install
  • root Yarn PnP polluted the nested npm/Vitest package, so root scripts now unset NODE_OPTIONS
  • local Playwright smoke needs a fixed-port server helper to avoid port roulette
• verification evidence:
  • bun test src/core
  • yarn workspace slate-browser test
  • PLAYWRIGHT_BASE_URL=http://localhost:3200 yarn test:slate-browser:e2e
  • PLAYWRIGHT_BASE_URL=http://localhost:3200 yarn test:slate-browser:ime
  • yarn build:rollup
  • yarn lint:typescript
  • LSP diagnostics 0 on new TS files
• architect verdict: APPROVE

2026-04-04

• continuing from the first tranche into the next real backlog slice:
  • empty-block IME composition on the placeholder path
  • DOM selection assertion fixture
  • clipboard contract fixture
  • persistent annotation anchor regression
  • zero-width shape fixtures
  • shared Playwright helper assertions
• loaded the current slate-browser docs plus the narrow solution docs first
• current evidence before edits:
  • IME must stay real-browser only
  • zero-width selection must normalize both directions
  • clipboard semantics and clipboard DOM transport are different seams
• current failures to resolve honestly:
  • Playwright helper smoke asserts the wrong initial caret position on the placeholder example
  • synthetic HTML paste through the current Playwright helper does not prove real paste behavior and currently does not update the editor
• landed the first real follow-up tranche in .tmp/slate-v2:
  • assertSelection now normalizes FEFF zero-width DOM offsets back to Slate offset 0
  • assertDomSelection stays raw and proves the browser is really at native offset 1 on the placeholder path
  • Vitest browser fixtures now pin both FEFF-backed and -only zero-width shapes
  • Playwright IME proof on the empty-block placeholder path is green
  • clipboard contract fixture moved off flaky OS clipboard reads and onto browser DOM transport with a synthetic copy event plus captured payload
  • helper selectAllInEditor(...) now waits for selection sync before selection-sensitive helper assertions
  • Playwright helper DX is now fronted by an editor-first harness:
    • const editor = await openExample(page, name)
    • editor.focus()
    • editor.type(...)
    • editor.press(...)
    • editor.selectAll()
    • editor.assert.text/html/selection/domSelection/placeholderVisible
    • editor.clipboard.copy/copyPayload
    • editor.ime.enableKeyEvents/compose
  • existing standalone helper functions remain as thin wrappers for now
• explicit current state:
  • persistent annotation anchor coverage is now split across:
    • mounted-runtime assertions in slate-react-v2
    • a dedicated hidden site example plus Playwright browser regression
• verification evidence:
  • yarn workspace slate-browser test
  • PLAYWRIGHT_BASE_URL=http://localhost:3200 yarn test:slate-browser:e2e
  • PLAYWRIGHT_BASE_URL=http://localhost:3200 yarn test:slate-browser:ime
  • PLAYWRIGHT_BASE_URL=http://localhost:3200 yarn test:slate-browser:clipboard
  • PLAYWRIGHT_BASE_URL=http://localhost:3200 yarn test:slate-browser:anchors
  • yarn workspace slate-react-v2 test
  • yarn build:rollup
  • yarn lint:typescript