diffPlayerUpdate runs once per player per tick on the worker thread. The
array/object fields (outgoingAttacks, incomingAttacks, alliances,
outgoingEmojis) were compared via JSON.stringify — two string allocations per
field, run on every call even when nothing changed. This made the cost flat at
~3.4µs/call regardless of what actually changed.
Replace jsonEqual with three typed structural comparators (attackArrayEqual,
allianceArrayEqual, emojiArrayEqual) that short-circuit on reference/length,
compare known fields with ===, early-exit on the first difference, and
allocate nothing — matching the existing numberArrayEqual/stringArrayEqual
style. ~9-10x faster across all cases (276k -> 2.4M ops/sec when unchanged).
Add tests/perf/DiffPlayerUpdatePerf.ts (BEFORE/AFTER benchmark, run via
npm run perf) and warnings on PlayerUpdate and diffPlayerUpdate noting that new
fields must be wired into the diff/apply functions or their changes are
silently dropped after the first emission.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
evanpelle
be87c7658f