@imikailoby/sats/dist/psbt/index.js

Tiny non-custodial Bitcoin SDK (TS) — keys, addresses, PSBT, provider chain

import * as bitcoin from "bitcoinjs-lib";
import { ECPairFactory } from "ecpair";
import * as ecc from "tiny-secp256k1";
import { network } from "../net/index";
import { ecPairToSigner } from "../crypto/signer";
import { InsufficientFundsError, PsbtBuildError } from "../core/errors";
import { toBuffer } from "../utils/bytes";
bitcoin.initEccLib(ecc);
const ECPair = ECPairFactory(ecc);
/** Sum input values in satoshis. */
export function sumInputs(utxos) {
    return utxos.reduce((s, u) => s + u.value, 0);
}
/** Sum output values plus a fixed fee. */
export function sumOutputs(outputs, fee) {
    return outputs.reduce((s, o) => s + o.value, 0) + fee;
}
/** Calculate non-negative change amount. */
export function calcChange(totalIn, totalOut) {
    return Math.max(0, totalIn - totalOut);
}
/**
 * Build a PSBT for P2WPKH-like inputs.
 * @throws PsbtBuildError | InsufficientFundsError
 */
export function buildPsbt(params) {
    const n = network(!!params.testnet);
    const psbt = new bitcoin.Psbt({ network: n });
    if (params.fee < 0)
        throw new PsbtBuildError("fee must be >= 0");
    params.outputs.forEach((o) => {
        if (o.value <= 0)
            throw new PsbtBuildError("output value must be > 0");
    });
    const totalIn = sumInputs(params.utxos);
    const totalOut = sumOutputs(params.outputs, params.fee);
    if (totalOut > totalIn)
        throw new InsufficientFundsError("insufficient funds");
    params.utxos.forEach((u) => {
        psbt.addInput({
            hash: u.txid,
            index: u.vout,
            witnessUtxo: {
                value: u.value,
                // Require provided scriptPubKey for correctness; fallback stays for BC but is discouraged.
                script: u.scriptPubKey
                    ? Buffer.from(u.scriptPubKey, "hex")
                    : bitcoin.address.toOutputScript(params.changeAddress, n),
            },
        });
    });
    params.outputs.forEach((o) => psbt.addOutput({ address: o.address, value: o.value }));
    const change = calcChange(totalIn, totalOut);
    if (change > 0)
        psbt.addOutput({ address: params.changeAddress, value: change });
    return psbt;
}
/** Sign PSBT with WIF or raw private key. */
export function signPsbt(psbt, priv, testnet) {
    const kp = typeof priv === "string"
        ? ECPair.fromWIF(priv, network(!!testnet))
        : ECPair.fromPrivateKey(toBuffer(priv), { network: network(!!testnet) });
    psbt.signAllInputs(ecPairToSigner(kp));
    return psbt;
}
/** Finalize all inputs and return hex and txid. */
export function finalizePsbt(psbt) {
    psbt.finalizeAllInputs();
    const tx = psbt.extractTransaction();
    return { hex: tx.toHex(), txid: tx.getId() };
}