# `Events['history:changed']`

> Contract 2.0.0 · package sha256 `a857eca95b35921109faf997094bb4192f12527d9d0fcd4be7e97f06425bad6e` · generated from `configurator-runtime.d.ts` by `services/onsite-scripter/scripts/build-contract-docs.mjs`; edit the source, not this file.

Property of [`Events`](Events.md) · stable · since 2.0.0

```ts
'history:changed': {
  readonly cause: Cause;
} & Pick<History, 'canUndo' | 'canRedo' | 'undoLabel' | 'redoLabel' | 'depth'>;
```

The undo state changed: the same fields as [`session.history`](Session.history.md). Also fired by an equal undo,
redo or `undo: 'rebase'` write, which makes no commit: its `cause` then carries the current
`seq` and `revision` (spec section 6.1, O9 and O15).

## Generic-API test (spec 3.1)

| Rule | Result |
| --- | --- |
| 1. Neutral name | pass: `history:changed` names no product |
| 2. A precedent | not recorded: no ledger row (coverage.json) names this member or its owner |
| 3. Two apps, or labs | pass: 21 apps (fleet cross-check: app-04c2774145, app-0c773a4ee3, app-37356bf09f, app-378d190f1b, app-4762caacdc, app-4fd23bc869, app-822bb9d6aa, app-8675b3225c and 13 more) |
| 4. The cheaper fix first | not recorded per member (Appendix B decides it per need) |