Unlock from hodlocker

unlock.js

const getUTXO = (rawtx, idx) => {
    const bsvtx = new bsv.Transaction(rawtx);
    return {
        satoshis: bsvtx.outputs[idx].satoshis,
        vout: idx,
        txid: bsvtx.hash,
        script: bsvtx.outputs[idx].script.toHex()
    }
}
const getRawtx = async txid => {
    const r = await fetch(`https://api.whatsonchain.com/v1/bsv/main/tx/${txid}/hex`);
    const raw = await r.text();
    return raw;
}
const unlockToken = (txHex, inputIndex, lockTokenScript, satoshis, privkey) => {
    const tx = new bsv.Transaction(txHex);
    const sighashType = bsv.crypto.Signature.SIGHASH_ALL | bsv.crypto.Signature.SIGHASH_FORKID;
    const scriptCode = bsv.Script.fromHex(lockTokenScript);
    const value = new bsv.crypto.BN(satoshis);
    // create preImage of current transaction with valid nLockTime
    const preimg = bsv.Transaction.sighash.sighashPreimage(tx, sighashType, inputIndex, scriptCode, value).toString('hex');
    let s;
    if (privkey) { // sign transaction with private key tied to public key locked in script
        s = bsv.Transaction.sighash.sign(tx, privkey, sighashType, inputIndex, scriptCode, value).toTxFormat();
    }
    return bsv.Script.fromASM(`${s.toString('hex')} ${privkey.toPublicKey().toHex()} ${preimg}`).toHex();
}
const unlockLock = async() => {
    const txid = '';
    const rawtx = await getRawtx(txid);
    const oIdx = 0;
    const lockedUTXO = getUTXO(rawtx, oIdx);
    const bsvtx = bsv.Transaction();;
    bsvtx.addInput(new bsv.Transaction.Input({
        prevTxId: txid,
        outputIndex: oIdx,
        script: new bsv.Script()
    }), bsv.Script(lockedUTXO.script), lockedUTXO.satoshis);
    bsvtx.lockUntilBlockHeight(); // populate with block height after locked height
    bsvtx.to('', lockedUTXO.satoshis - 1); // set receive address here
    // WIF is m/0’/236’/0’/0/0 of RelayX Mnemonic
    const solution = unlockToken(bsvtx.toString(), oIdx, lockedUTXO.script, lockedUTXO.satoshis, bsv.PrivateKey.fromWIF(''));
    bsvtx.inputs[oIdx].setScript(solution)
    console.log(bsvtx.toString())
    return bsvtx.toString();
}

Requires bsv legacy library - https://github.com/moneybutton/bsv/tree/bsv-legacy