Skip to content

getL2Output

Retrieves an L2 output proposal that covers a provided L2 block number. Used for the Withdrawal flow.

By default (strategy: 'latest') it returns the latest committed output that covers the block. Proving against the latest output reads the storage proof at a recent L2 block, so it avoids an archive RPC dependency for old withdrawals — without changing the finalize waiting time (which is measured from the prove timestamp). Pass strategy: 'earliest' to restore the historical "first covering output" behaviour.

With strategy: 'latest', the call throws LatestL2OutputNotReadyError when no committed output yet covers the block (whereas strategy: 'earliest' reverts via the L2 Output Oracle). Both map to a waiting-to-prove status in getWithdrawalStatus.

Usage

example.ts
import { mantle } from '@mantleio/viem/chains'
import { account, publicClientL1 } from './config'
 
const output = await publicClientL1.getL2Output({ 
  l2BlockNumber: 69420n, 
  targetChain: mantle, 
})

Returns

GetL2OutputReturnType

The L2 output proposal.

Parameters

l2BlockNumber

  • Type: bigint

The L2 block number.

const output = await publicClientL1.getL2Output({
  l2BlockNumber: 69420n, 
  targetChain: mantle,
})

strategy (optional)

  • Type: 'latest' | 'earliest'
  • Default: 'latest'

Which output to return for the given block. 'latest' returns the most recently committed output covering the block (avoids an archive RPC dependency for old withdrawals); 'earliest' returns the first covering output.

const output = await publicClientL1.getL2Output({
  l2BlockNumber,
  strategy: 'earliest', 
  targetChain: mantle,
})

targetChain

The L2 chain.

const output = await publicClientL1.getL2Output({
  l2BlockNumber,
  targetChain: mantle, 
})

l2OutputOracleAddress (optional)

  • Type: Address
  • Default: targetChain.contracts.l2OutputOracle[chainId].address

The address of the L2 Output Oracle contract. Defaults to the L2 Output Oracle contract specified on the targetChain.

If a l2OutputOracleAddress is provided, the targetChain parameter becomes optional.

const output = await publicClientL1.getL2Output({
  l2BlockNumber,
  l2OutputOracleAddress: '0xbEb5Fc579115071764c7423A4f12eDde41f106Ed', 
})