# fund

Funds a Bitcoin transaction.

# Type

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

# Syntax

await computer.fund(tx)

# Parameters

# tx

A Bitcoin transaction object from the NakamotoJS library.

# opts

An optional object can be passed as parameter to include or exclude certain UTXOs. When using include, the transaction will be funded with the UTXOs specified as the first inputs.

Key	Type	Description	Default Value
include	string[]	UTXOs to include	[]
exclude	string[]	UTXOs to exclude	[]

# Return value

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

# Examples

// A smart contract
class C extends Contract {}

// Encode a constructor call without funding the transaction
const computer1 = new Computer({ mnemonic: ... })
const { tx } = await computer1.encode({
  exp: `${C} new ${C.name}()`
  fund: false
})

// Fund the transactions (can be another computer)
const computer2 = new Computer({ mnemonic: ... })
await computer1.fund(tx)

// Broadcast the tx
const txId = await computer2.broadcast(tx)