R4A.1 opens the operations layer of the V2 engine. Pure functions only;
no provider coupling. Lives in `engine/operations-v2/`. The full V1
op surface (~50 functions, ~3000 lines) splits across multiple R4A.*
sprints — this one establishes the foundation + the V2-exclusive
visual operation that unlocks POLISH-1b in later sprints.
operations-v2/types.ts (~55 lines):
- WordsEditorStateV2 = { document, selection, activeMarks } over V2
shapes. Reuses V1's `WordsSelection` (path + offset) verbatim — the
selection model doesn't change between V1 and V2.
- WordsOperationResultV2 = { state, changed }. Same shape as V1's
result so future provider migration can plug in directly.
- noOp + changed helpers for guard-clause and result construction.
operations-v2/normalize.ts (~250 lines):
- normalizeDocumentV2(doc, opts?) — defensive shape repair after
every operation. Returns same document REFERENCE when nothing
changed (cheap structural compare via mutated flag).
- Autogen `id` for blocks/items/rows/cells without one (delegates
to defaultIdGenerator from migrate-v2 → crypto.randomUUID + fallback).
- Seeds empty containers: empty document → 1 paragraph; empty list
→ 1 item; empty table → 1×1 cell; empty inline children → 1
empty text.
- Coalesces adjacent text inlines with identical marks (V1 invariant
preserved — keeps the model from fragmenting after edits).
- Strips marks from code block children (code is plain text only).
operations-v2/visual.ts (~115 lines):
- setBlockVisual(state, blockIndex, patch) — V2-EXCLUSIVE.
- Shallow-merges patch into block.visual. Defends:
* blockIndex must be valid.
* Every patch key must be in WORDS_VISUAL_KEYS_PER_TYPE[block.type]
(P8 whitelist enforced at runtime; unknown keys silently dropped).
* Patch values of `undefined` REMOVE the corresponding visual
property from the merged result (clears via undefined).
* Empty visual is omitted from the block (no `visual: {}` stored).
* No-op result when patch matches existing visual (avoids
spurious re-renders).
- This is the operation POLISH-1b (image radius slider + shadow
toggles + border controls) will call.
operations-v2/block.ts (~140 lines):
- updateBlockAt(state, blockIndex, patch) — shallow-merges block
fields, refuses to change `type`.
- deleteBlockAt(state, blockIndex) — removes block; normalizer
seeds an empty paragraph if it was the last.
- insertBlockAt(state, blockIndex, block) — inserts at index (clamps
to bounds).
- moveBlockAt(state, blockIndex, direction) — swap with neighbor.
- duplicateBlockAt(state, blockIndex) — inserts a copy with a fresh
autogen id (drops the original's id before normalize so they're
distinguishable).
- moveBlockToAt(state, fromIndex, toIndex) — arbitrary repositioning
for drag-drop.
operations-v2/index.ts: barrel export of the public surface.
Tests (31): normalize (autogen ids preserved when present, empty
containers seeded for doc/list/table/inline children, text coalescing
with marks-aware preservation, code stripping, idempotence via same
reference). setBlockVisual (set/merge/clear/empty-elision/per-type
whitelist enforcement/shadow on image vs paragraph/no-op on match).
Block ops (updateBlockAt with type-change refusal + invalid index
no-op; deleteBlockAt with seed-on-empty; insertBlockAt with clamping;
moveBlockAt with edge no-op; duplicateBlockAt with fresh id;
moveBlockToAt with from-equals-to no-op).
Two TS errors landed mid-write (over-clever readonly modifier on
function param + structural cast across discriminated union) — both
fixed with simpler types. Verification: 257/257 engine tests pass
(85 V1 + 50 V2 validator + 35 V2 migrator/parity + 56 V2 render/
serializers + 31 V2 ops). `npm run check`: 0 errors.
Next: R4A.2 — text + selection operations (insertText, deleteRange,
insertParagraph, deleteBackward, deleteForward, toggleMark, etc.).
~2500 lines of V1 to mechanically translate. Or pause R4 entirely
and tackle the pragmatic shortcut (backport visual to V1 image to
ship POLISH-1b sooner).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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