# ConditionalEvent

- [YAML representation](https://developers.google.com/assistant/actionssdk/reference/rest/Shared.Types/ConditionalEvent#SCHEMA_REPRESENTATION)

Registers events that trigger as the result of a true condition.

| YAML representation ||
|---|---|
| ``` condition: string transitionToScene: string handler: object (`https://developers.google.com/assistant/actionssdk/reference/rest/Shared.Types/EventHandler`) ``` |

| Fields ||
|---|---|
| `condition` | `string` Required. Filter condition for this event to trigger. If condition is evaluated to true then the associated `handler` will be triggered. The following variable references are supported: `$session` - To reference data in session storage. `$user` - To reference data in user storage. The following boolean operators are supported (with examples): `&&` - `session.params.counter > 0 && session.params.counter < 100` `||` - `session.params.foo == "John" || session.params.counter == "Adam"` `!` - `!(session.params.counter == 5)` The following comparisons are supported: `==`, `!=`, `<`, `>`, `<=`, `>=` The following list and string operators are supported (with examples): `in` - "Watermelon" in `session.params.fruitList` `size` - `size(session.params.fruitList) > 2` `substring` - `session.params.fullName.contains("John")` |
| `transitionToScene` | `string` Optional. Destination scene which the conversation should jump to when the associated condition is evaluated to true. The state of the current scene is destroyed on the transition. |
| `handler` | ``object (`https://developers.google.com/assistant/actionssdk/reference/rest/Shared.Types/EventHandler`)`` Optional. Event handler which is triggered when the associated condition is evaluated to `true`. Should execute before transitioning to the destination scene. Useful to generate Prompts in response to events. |