@bsv/sdk/src/compat/Utxo.ts

BSV Blockchain Software Development Kit

import Transaction from '../transaction/Transaction.js'
import TransactionInput from '../transaction/TransactionInput.js'
import LockingScript from '../script/LockingScript.js'
import UnlockingScript from '../script/UnlockingScript.js'

interface jsonUtxo {
  txid: string
  vout: number
  satoshis: number
  script: string
}
/**
 * @method fromUtxo
 *
 * @description
 * This function creates a transaction input from a utxo json object
 * The idea being old code that uses utxos rather than sourceTranactions can convert using this.
 *
 * @deprecated
 * This approach is made available for compatibility only. It is deprecated in favor of using sourceTransactions
 * directly. It's recommended that wallets general keep transactions which store unspent outputs in their entirety,
 * along with corresonding Merkle paths. The reason you would keep the whole transaction is such that you can prove
 * the txid, and therefore its inclusion within a specific block.
 *
 * @example
 * const i = fromUtxo({
 *   txid: '434555433eaca96dff6e71a4d02febd0dd3832e5ca4e5734623ca914522e17d5',
 *   vout: 0,
 *   script: '51',
 *   satoshis: 1234
 * }, new P2PKH().unlock(p))
 *
 * tx.addInput(i)
 *
 * @param utxo: jsonUtxo
 * @param unlockingScriptTemplate: { sign: (tx: Transaction, inputIndex: number) => Promise<UnlockingScript>, estimateLength: (tx: Transaction, inputIndex: number) => Promise<number> }
 * @returns
 */
export default function fromUtxo (
  utxo: jsonUtxo,
  unlockingScriptTemplate: {
    sign: (tx: Transaction, inputIndex: number) => Promise<UnlockingScript>
    estimateLength: (tx: Transaction, inputIndex: number) => Promise<number>
  }
): TransactionInput {
  const sourceTransaction = new Transaction(0, [], [], 0)
  sourceTransaction.outputs = Array(utxo.vout + 1).fill(null)
  sourceTransaction.outputs[utxo.vout] = {
    satoshis: utxo.satoshis,
    lockingScript: LockingScript.fromHex(utxo.script)
  }
  return {
    sourceTransaction,
    sourceTXID: utxo.txid,
    sourceOutputIndex: utxo.vout,
    unlockingScriptTemplate,
    sequence: 0xffffffff
  }
}