# waitForEvent

Waits for a specific event matching a given request ID by combining a WebSocket listener (real-time) with polling backfill (resilience). Use this when invoking the `sign` instruction on the contract without using this class's `sign` method (e.g. for cross-contract invocations or bidirectional flows).

## Usage

```ts twoslash
// [!include ~/snippets/code/solana/fee-delegation.ts]
const solanaChainSigContract = chainSigContract

const requestId = '0x...'
const txSignature = 'signatureOfTheSignRequestTransaction'
// ---cut---
import { PublicKey } from '@solana/web3.js'

const controller = new AbortController()

const signature = await solanaChainSigContract.waitForEvent({
  eventName: 'signatureRespondedEvent',
  requestId,
  signer: new PublicKey('ResponderPublicKeyHere'),
  afterSignature: txSignature,
  timeoutMs: 60_000,
  signal: controller.signal,
})
```

## Waiting for a Bidirectional Response

```ts twoslash
// [!include ~/snippets/code/solana/fee-delegation.ts]
const solanaChainSigContract = chainSigContract

const requestId = '0x...'
const txSignature = 'signatureOfTheSignRequestTransaction'
// ---cut---
import { PublicKey } from '@solana/web3.js'

const controller = new AbortController()

const result = await solanaChainSigContract.waitForEvent({
  eventName: 'respondBidirectionalEvent',
  requestId,
  signer: new PublicKey('ResponderPublicKeyHere'),
  afterSignature: txSignature,
  timeoutMs: 60_000,
  signal: controller.signal,
})

// result.serializedOutput - Buffer with the destination chain execution result
// result.signature - raw Signature { bigR, s, recoveryId }
```

## Parameters

| Parameter                | Type                       | Description                                                                                                                               |
| ------------------------ | -------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------- |
| `eventName`              | `ChainSignaturesEventName` | Event to listen for (`'signatureRespondedEvent'`, `'signatureErrorEvent'`, or `'respondBidirectionalEvent'`)                              |
| `requestId`              | `string`                   | Unique identifier for the signature request                                                                                               |
| `signer`                 | `PublicKey`                | Address to monitor for transactions (e.g. responder address)                                                                              |
| `afterSignature?`        | `string`                   | Transaction signature to start polling from                                                                                               |
| `timeoutMs?`             | `number`                   | Timeout in milliseconds (default: 60000)                                                                                                  |
| `backfillIntervalMs?`    | `number`                   | Interval between backfill polls in milliseconds (default: 30000)                                                                          |
| `backfillLimit?`         | `number`                   | Max transactions to fetch per backfill poll (default: 50)                                                                                 |
| `healthCheckIntervalMs?` | `number`                   | Interval in milliseconds for WebSocket health checks. Triggers reconnection and fast backfill if the connection is lost. (default: 10000) |
| `signal?`                | `AbortSignal`              | Abort signal for cancellation                                                                                                             |

## Returns

The return type depends on the `eventName`:

| Event Name                  | Return Type                         | Description                                                         |
| --------------------------- | ----------------------------------- | ------------------------------------------------------------------- |
| `signatureRespondedEvent`   | `Promise<RSVSignature>`             | The signature in RSV format                                         |
| `signatureErrorEvent`       | `Promise<SignatureErrorData>`       | Error details from the signing request                              |
| `respondBidirectionalEvent` | `Promise<RespondBidirectionalData>` | Serialized output and raw signature from the bidirectional response |