> ## Documentation Index
> Fetch the complete documentation index at: https://javascript.wapikit.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Handle Events

> Learn how to handle events using the Wapi.js SDK

Wapi.js SDK implements Node.js native EventEmitter class to implment event handling.

## Listen to Events:

You can listen to events using the `on` method available on the [client](api-reference/classes/Client) class. Here is an example of how you can listen to incoming messages and reply/react to them:

```typescript theme={null}
// assuming you have already initiated the client,


whatsappClient.on('Ready', async () => {
        console.log("Client is ready to receive messages.")
})

whatsappClient.on('Error', async error => {
        console.errpr("An error occured.", error)
})

whatsappClient.on('TextMessage', async message => {
        await message.reply({
            message: new TextMessage({
                text: 'This is a reply.'
            })
        })
})

whatsappClient.on('AudioMessage', async message => {
        await message.reply({
            message: new TextMessage({
                text: 'This is a reply.'
            })
        })
})

// and so on for other message types...

```

## Exposed Events

The SDK supports the following events out of the box to make it easy to handle both the user and system events:

<Note>There is no messaging or system event handling differences in the SDK, here they are just bifurcated for the educational puposes.</Note>

### Messaging Events:

* [Text Message Event](/api-reference/classes/TextMessageEvent)
* [Image Message Event](/api-reference/classes/ImageMessageEvent)
* [Video Message Event](/api-reference/classes/VideoMessageEvent)
* [Audio Message Event](/api-reference/classes/AudioMessageEvent)
* [Document Message Event](/api-reference/classes/DocumentMessageEvent)
* [Location Message Event](/api-reference/classes/LocationMessageEvent)
* [Contact Message Event](/api-reference/classes/ContactMessageEvent)
* [Reaction Message Event](/api-reference/classes/ReactionMessageEvent)
* [Sticker Event](/api-reference/classes/StickerMessageEvent)
* [Quick Reply Button Interaction Event](api-reference/interfaces/QuickReplyButtonInteractionEvent)
* [Ad Interaction Event](/api-reference/classes/AdInteractionEvent)
* [Product Inquiry Event](/api-reference/classes/ProductInquiryEvent)
* [Reply Button Interaction Event](/api-reference/classes/ReplyButtonInteractionEvent)
* [List Interaction Event](/api-reference/classes/ListInteractionEvent)

<Card title="Important" icon="code" iconType="duotone" color="#ca8b04">
  Each of the events mentioned above has a couple of utility methods available like `reply`, `react` etc. which can be used to reply or react to the incoming messages.
</Card>

### System Events

* Client Ready Event
* Client Error Event
* [Message Delivered Event](/api-reference/classes/MessageDeliveredEvent)
* [Message Read Event](/api-reference/classes/MessageReadEvent)
* [Message Sent Event](/api-reference/classes/MessageSentEvent)
* [Message Failed Event](/api-reference/classes/MessageReceivedEvent)
* [Message Undelivered Event](/api-reference/classes/MessageUndeliveredEvent)
* [Customer Identity Changed Event](/api-reference/classes/CustomerIdentityChangedEvent)
* [Customer Number Changed Event](/api-reference/classes/CustomerNumberChangedEvent)