# Bus The web client `env` contains an event bus, named `bus`. Its purpose is to allow various parts of the system to properly coordinate themselves, without coupling them. The `env.bus` is an owl `EventBus`, that should be used for global events of interest. ## Message List | Message | Payload | Triggered when: | Addon | | --------------------------- | ----------------------------------------------------------------------------------------- | ------------------------------------------------------------------- | ----- | | `ACTION_MANAGER:UI-UPDATED` | a mode indicating what part of the ui has been updated ('current', 'new' or 'fullscreen') | the rendering of the action requested to the action manager is done | wowl | | `ACTION_MANAGER:UPDATE` | next rendering info | the action manager has finished computing the next interface | wowl | | `MENUS:APP-CHANGED` | none | the menu service's current app has changed | wowl | | `NOTIFICATIONS_CHANGE` | list of notifications | the list of notifications changes | wowl | | `ROUTE_CHANGE` | none | the url hash was changed | wowl | | `RPC_ERROR` | error data object | a rpc request (going through `rpc` service) fails | wowl | | `RPC:REQUEST` | rpc id | a rpc request has just started | wowl | | `RPC:RESPONSE` | rpc id | a rpc request is completed | wowl | | `WEB_CLIENT_READY` | none | the web client has been mounted | wowl |