LogIndex

Log position in receipt (0-based)

Overview

LogIndex is a branded number type representing a log’s position within a transaction receipt. Indices start at 0 for the first log emitted.

import * as LogIndex from '@tevm/primitives/LogIndex'

const index = LogIndex.from(2)

Type Definition

type LogIndexType = number & {
  readonly [brand]: "LogIndex";
}

Creating LogIndexes

from

Create from number or bigint.

// From number
const idx1 = LogIndex.from(2)

// From bigint
const idx2 = LogIndex.from(2n)

// First log
const first = LogIndex.from(0)

Validation: Must be non-negative integer.

Converting LogIndexes

toNumber

Convert to number (zero-cost).

const num = LogIndex.toNumber(index)
// 2

Comparing LogIndexes

equals

Check equality.

const a = LogIndex.from(2)
const b = LogIndex.from(2)

if (LogIndex.equals(a, b)) {
  console.log('Indexes are equal')
}

Usage in Event Logs

LogIndex appears in event logs to indicate position within a receipt:

import * as EventLog from '@tevm/primitives/EventLog'

const log = {
  logIndex: LogIndex.from(2),
  address: contractAddress,
  topics: [eventSignature],
  data: eventData
}

Errors

InvalidLogIndexError: Invalid value (negative, non-integer, wrong type).

See Also

• EventLog - Event logs
• Receipt - Transaction receipts
• TransactionIndex - Transaction position