# Lifecycle hooks

**@node-ts/bus** exposes a number of lifecycle hooks that can be subscribed to. These are **EventEmitter** instances that follow the standard node `.on()` and `.off()` notation.

### Hooks

**beforeSend**

called just before a command is sent to the underlying transport

```
bus.beforeSend.on(({ command, attributes }) => {})
```

**beforePublish**

called just before a event is published to the underlying transport

```
bus.beforePublish.on(({ event, attributes }) => {})
```

**afterReceive** 

called after a message has been read from the queue, and before it is dispatched to handlers

```
bus.afterReceive.on(transportMessage => {})
```

**beforeDispatch**

called before a message is dispatched to its handlers

```
bus.beforeDispatch.on(({ message, attributes, handlers }) => {})
```

**afterDispatch**

called after a message has been successfully handled and the message deleted from the transport

```
bus.afterDispatch.on(({ message, attributes }) => {})
```

**onError**

called when an error occurred reading/dispatching/handling a message

```
bus.onError.on(({ message, error, attributes, rawMessage }) => {})
```