TransactionIndex

Transaction position in block (0-based)

Overview

TransactionIndex is a branded number type representing a transaction’s position within a block. Indices start at 0 for the first transaction in a block.

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

const index = TransactionIndex.from(5)

Type Definition

type TransactionIndexType = number & {
  readonly [brand]: "TransactionIndex";
}

Creating TransactionIndexes

from

Create from number or bigint.

// From number
const idx1 = TransactionIndex.from(5)

// From bigint
const idx2 = TransactionIndex.from(5n)

// First transaction in block
const first = TransactionIndex.from(0)

Validation: Must be non-negative integer.

Converting TransactionIndexes

toNumber

Convert to number (zero-cost).

const num = TransactionIndex.toNumber(index)
// 5

Comparing TransactionIndexes

equals

Check equality.

const a = TransactionIndex.from(5)
const b = TransactionIndex.from(5)

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

Usage in Receipts

TransactionIndex appears in transaction receipts to indicate position within a block:

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

const receipt = Receipt.from({
  transactionIndex: TransactionIndex.from(3),
  // ... other fields
})

Errors

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

See Also

• Receipt - Transaction receipts
• LogIndex - Log position
• TransactionHash - Transaction identifier