# Problem code `'unknown-event'`

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

A member of [`ProblemCode`](../api/ProblemCode.md) · stable · since 2.0.0

[`on()`](../api/Session.on.md) got an event name that doesn't exist; it subscribed to nothing.

## What to do

The Problem's `didYouMean` names the event meant: a removed 1.x name's 2.0 event first ('scene:synced' is 'scene-model:changed', 'material:changed' is 'material:selected', 'scene:settled' and 'history:restored' are 'committed'), then close names. Use a key of [`Events`](../api/Events.md): 'committed' (every commit), 'scene-model:changed' (the model, with `model`), 'material:selected', 'history:changed', 'assembly:changed', 'click', 'hover', 'drag:start', 'drag:move', 'drag:end', 'camera:changed', 'camera:rest', 'camera:control-start', 'camera:control-end', 'hotspot:click', 'hotspot:hover', 'anchors:moved', 'animation:started', 'animation:stopped', 'animation:finished', 'ar:status', 'ar:modes', 'resize', 'document:applied', 'problem', and the labs 'xr:start', 'xr:end' and 'xr:cta' (Holostep's in-page AR or try-on). [`Events`](../api/Events.md) is the full list.

```ts
session.on('scene-model:changed', ({ model }) => renderSummary(model), { signal });
```

## Where the declaration names it

- [`Problem.event`](../api/Problem.event.md): The event name, for 'handler-threw', 'handler-async', 'handler-rejected' and 'unknown-event'.
- [`Session.on`](../api/Session.on.md): Errors: an unknown event records 'unknown-event' and returns a no-op unsubscribe; a handler that throws records 'handler-threw', one that returns a Promise 'handler-async', and that Promise's rejection 'handler-rejected'.

The set is open: handle a code you don't know (`'other'`).