fund

Funds a Bitcoin transaction.

Type

(
  tx: NakamotoJS.Transaction,
  opts?: {
    include?: string[]
    exclude?: string[]
  }
): Promise<void>

Parameters

`tx`

A NakamotoJS transaction object or a Bitcoin Computer Transaction object (Bitcoin Computer’s Transaction extends NakamotoJS).

`opts`

Optional UTXO selection. When include is set, those UTXOs are preferred as funding inputs.

Key	Description	Default
include	UTXOs to prefer as inputs	`[]`
exclude	UTXOs to avoid	`[]`

Fee rate is controlled via setFee / getFee (satPerByte), not via fund options.

UTXOs are encoded as <transaction-id>:<output-number>.

Return Value

If the wallet does not have sufficient funds, an error is thrown.

Example

import { Computer } from '@bitcoin-computer/lib'
import { address, networks, Transaction } from '@bitcoin-computer/nakamotojs'
import { chain, network, url } from '../../utils/index.js'

describe('fund', () => {
  let computer: Computer

  before('Create and fund wallet', async () => {
    computer = new Computer({ chain, network, url })
    await computer.faucet(1e8)
  })

  it('Should fund a NakamotoJS transaction', async () => {
    // Build a transaction with NakamotoJS
    const tx = new Transaction()
    const { regtest } = networks
    const outputScript = address.toOutputScript('mkHS9ne12qx9pS9VojpwU5xtRd4T7X7ZUt', regtest)
    tx.addOutput(outputScript, BigInt(1e5))

    // Fund, sign and broadcast transaction
    await computer.fund(tx)
    await computer.sign(tx)
    await computer.broadcast(tx)
  })

  it('Should fund a Bitcoin Computer transaction', async () => {
    // Build a transaction with the Bitcoin Computer library
    const { tx } = await computer.encode({
      exp: `class C extends Contract {}; new C()`,
      fund: false,
    })

    // Fund, sign and broadcast transaction
    await computer.fund(tx!)
    await computer.sign(tx!)
    await computer.broadcast(tx!)
  })
})

Source