Slate v2 React Scan Experiment Loop

Goal

Use react-scan as a local microscope while pushing huge-document runtime work forward, without confusing profiler visuals for benchmark truth.

Decision

• use react-scan only as an opt-in dev profiler
• do not make it a benchmark gate
• do not add a permanent package dependency for it yet
• load it only when ?reactScan=1 is present in the site app

Why

• the kept rerender-breadth lane already proved descendant invalidation is mostly local
• the remaining huge-document gap is likely large-doc DOM/runtime policy, not generic “React rerenders”
• react-scan can still help spot accidental broad mounts or promotion churn during future large-document experiments

Immediate Use

Profile these flows in site with ?reactScan=1:

1. huge-document typing at 5000 and 10000
2. future shell-promotion experiments
3. any broad-op regression around Ctrl+A and paste

Guardrails

• benchmark scripts stay the source of truth
• if react-scan and the kept lanes disagree, trust the lanes
• if it does not change a design decision, stop staring at it