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# `l1.waitForNextL2Output`

Waits for a legacy L2 output after an L2 block number.

## Usage

Poll until the L2 Output Oracle contains an output that covers the requested block.

:::code-group
```ts twoslash [example.ts]
import { optimism } from 'viem/chains'
import { client } from './viem.config'

const output = await client.output.waitForNextL2Output({ // [!code focus]
  l2BlockNumber: 123_456_789n, // [!code focus]
  targetChain: optimism, // [!code focus]
}) // [!code focus]
```

```ts twoslash [viem.config.ts] filename="viem.config.ts"
// [!include ~/snippets/op-stack/l1.config.ts:setup]
```
:::

### Standalone Action

Call `Actions.l1.waitForNextL2Output` directly by passing the [Client](/docs/clients) as the first argument.

:::code-group
```ts twoslash [example.ts]
import { optimism } from 'viem/chains'
import { Actions } from 'viem/op-stack'
import { client } from './viem.config'

const output = await Actions.l1.waitForNextL2Output(client, { // [!code focus]
  l2BlockNumber: 123_456_789n, // [!code focus]
  targetChain: optimism, // [!code focus]
}) // [!code focus]
```

```ts twoslash [viem.config.ts] filename="viem.config.ts"
// [!include ~/snippets/op-stack/l1.config.ts:setup]
```
:::

## Return Value

```ts
{
  l2BlockNumber: bigint
  outputIndex: bigint
  outputRoot: Hex
  timestamp: bigint
}
```

The next output that covers the requested L2 block.

## Parameters

### chain

* **Type:** `Chain`
* **Default:** `client.chain`

The L1 chain used to read the contracts.

### disputeGameFactoryAddress

* **Type:** `Address`

An explicit Dispute Game Factory address. Supply all three explicit addresses when omitting `targetChain`.

### intervalBuffer

* **Type:** `number`
* **Default:** `1.1`

The multiplier applied to the configured output interval before polling begins.

### l2BlockNumber

* **Type:** `bigint`

The minimum L2 block number for the next output.

### l2OutputOracleAddress

* **Type:** `Address`

An explicit L2 Output Oracle address. Supply all three explicit addresses when omitting `targetChain`.

### limit

* **Type:** `number`
* **Default:** `100`

The maximum number of dispute games inspected if output retrieval resolves through a portal claim.

### pollingInterval

* **Type:** `number`
* **Default:** `client.pollingInterval`

The polling interval in milliseconds.

### portalAddress

* **Type:** `Address`

An explicit Optimism Portal address. Supply all three explicit addresses when omitting `targetChain`.

### targetChain

* **Type:** `Chain`

The OP Stack L2 [Chain](/docs/chains) whose L1 contracts are used.