@bigmi/core
Version:
TypeScript library for Bitcoin apps.
53 lines • 1.99 kB
JavaScript
import { address, Psbt } from 'bitcoinjs-lib';
export function modifyFee(psbt, newFee, accountAddress) {
const newPsbt = new Psbt();
const inputs = psbt.data.inputs;
const outputs = psbt.txOutputs;
// Add inputs to the new PSBT
for (let i = 0; i < inputs.length; i++) {
const input = inputs[i];
const inputData = {
hash: psbt.txInputs[i].hash,
index: psbt.txInputs[i].index,
};
// Include UTXO information
if (input.nonWitnessUtxo) {
inputData.nonWitnessUtxo = input.nonWitnessUtxo;
}
else if (input.witnessUtxo) {
inputData.witnessUtxo = input.witnessUtxo;
}
// Include scripts if necessary
if (input.redeemScript) {
inputData.redeemScript = input.redeemScript;
}
if (input.witnessScript) {
inputData.witnessScript = input.witnessScript;
}
newPsbt.addInput(inputData);
}
const changeOutputScript = address.toOutputScript(accountAddress);
// Add outputs to the new PSBT
for (const output of outputs) {
const outputData = {
script: output.script,
value: output.value,
};
const scriptsAreEqual = output.script.length === changeOutputScript.length &&
output.script.every((value, index) => value === changeOutputScript[index]);
if (scriptsAreEqual) {
outputData.value = output.value - newFee;
if (outputData.value < 0) {
throw new Error('Insufficient funds to adjust the fee by the specified amount.');
}
}
newPsbt.addOutput(outputData);
}
// Modify the input sequence number to enable RBF
newPsbt.txInputs.forEach((_, index) => {
// Set sequence number to less than 0xfffffffe, e.g., 0xfffffffd
newPsbt.setInputSequence(index, 0xfffffffd);
});
return newPsbt;
}
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