> For the complete documentation index, see [llms.txt](https://ksdaemon.gitbook.io/wampy.js/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ksdaemon.gitbook.io/wampy.js/api/errors-handling.md).

# Errors handling

During wampy instance lifetime there can be many cases when error happens: some made by developer mistake, some are bound to WAMP protocol violation, some came from other peers. Errors that can be caught by wampy instance itself are stored in `opStatus.error`, while others are just thrown.

This allows, for example, convenient handling of different types of errors:

```javascript
import {Wampy, Errors} from 'wampy';
const wampy = new Wampy('/ws/', { realm: 'AppRealm' });

try {
    await wampy.call('start.migration');
    console.log('RPC successfully called');
} catch (e) {
    console.log('Error happened!');
    if (e instanceof Errors.UriError) {
        // statements to handle UriError exceptions
    } else if (e instanceof Errors.InvalidParamError) {
        // statements to handle InvalidParamError exceptions
    } else if (e instanceof Errors.NoSerializerAvailableError) {
        // statements to handle NoSerializerAvailableError exceptions
    } else {
        // statements to handle any unspecified exceptions
    }
}
```

Wampy package exposes next `Errors` classes:

* UriError
* NoBrokerError
* NoCallbackError
* InvalidParamError
* NoSerializerAvailableError
* NonExistUnsubscribeError
* NoDealerError
* RPCAlreadyRegisteredError
* NonExistRPCUnregistrationError
* NonExistRPCInvocationError
* NonExistRPCReqIdError
* NoRealmError
* NoWsOrUrlError
* NoCRACallbackOrIdError
* ChallengeExceptionError
* PPTNotSupportedError
* PPTInvalidSchemeError
* PPTSerializerInvalidError
* PPTSerializationError
* ProtocolViolationError
* AbortError
* WampError
* SubscribeError
* UnsubscribeError
* PublishError
* RegisterError
* UnregisterError
* CallError
* WebsocketError

For errors attributes look at src/errors.js file.


---

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