TypeError: BigInt value can't be serialized in JSON

[sir-stevie]

I have created and signed a transaction using btc-signer library but when I try to broadcast it to blockstream test network I get the error, "TypeError: BigInt value can't be serialized in JSON" and I have no idea what to do at this point. I tried incorporating some custom method to convert the transaction object to a json object before broadcasting it but that didn't work, I got an error that said "sendrawtransaction RPC error: {"code":-22,"message":"TX decode failed. Make sure the tx has at least one input."}". The following is the relevant part of the code am using,
"
// get inputs
async getInputs(network, fromAddress, privateKey) {
try {
const newPrivateKey = base58.decode(privateKey).slice(1, 33);

        // Fetch utxos to be used as inputs for this transaction 
        const firstResponse = await axios.get(`${corsProxyUrl}/${blockstreamUrl}/address/${fromAddress}/utxo`);
        const utxos = firstResponse.data;

        const inputs = [];
        
        var inputCount = 0; // loop counter
        for (const element of utxos) {
            const utxo = {
                amount: btc.Decimal.decode(`${element.value/100000000}`),
                index: inputCount,
                address: fromAddress,
                txid: element.txid,
                vout: element.vout,
                witnessUtxo: {
                    amount: btc.Decimal.decode(`${element.value/100000000}`),
                    script: btc.p2wpkh(secp256k1.publicKeyCreate(newPrivateKey, true), network).script,
                },
            };

            inputs.push(utxo);
            inputCount += 1;
        }

        return inputs;

    } catch(error) {
        this.handleError(error);
        console.log("An error occurred while getting inputs");
    }
}

// transaction to upload file
async txToUploadData(network, data, fromAddress, toAddress, privateKey, amount){
    try {
        const newPrivateKey = base58.decode(privateKey).slice(1, 33);
        const inputs = await this.getInputs(network, fromAddress, privateKey);

        console.log("Done getting inputs... ", inputs);

        // append data as output
        const dataIn = Buffer.from(data);
        const outputScript = Buffer.concat([
            Buffer.from([btc.OP.PUSHDATA1, dataIn.length]),
            dataIn
        ]);

        console.log("Script: ", outputScript);

        const outputs = [
            {
                address: toAddress, 
                script: outputScript,
                amount: 0n
            },
            {
                address: toAddress,
                amount: btc.Decimal.decode(`${amount}`)
            }
        ]

        console.log("Done setting outputs...");

        const selected = btc.selectUTXO(inputs, outputs, 'default', {
            changeAddress: fromAddress,
            feePerByte: 2n,
            bip69: true,
            createTx: true,
            network: network,
            allowUnknownOutputs: true
            
        });

        const {tx} = selected;
        tx.sign(newPrivateKey);
        tx.finalize();

        const headers = {
            "X-Requested-With": "XMLHttpRequest"
        }

        console.log("Transaction: ", JSON.stringify(tx));

        // broadcast the transaction
        const response = await axios({method: 'POST', url: `${corsProxyUrl}/${blockstreamUrl}/tx`, headers: headers, data: tx});

        // const response = axios.post(`${corsProxyUrl}/https://api.blockcypher.com/v1/bcy/test/txs/push`, JSON.stringify(pushtx))
        // .then(function(d) {console.log(d)});

        console.log("Done broadcasting transaction...", response.data);

        return tx;

    }catch(error) {
        console.log("An error occurred while sending 1st transaction");
        this.handleError(error);
    }
}
"

[victorkirov]

Try using tx.hex as the data field when making the request to blockstream

[victorkirov]

Your output script looks a bit strange. What are you trying to do exactly? 🤔

[sir-stevie]

Am trying to transfer bitcoin from one wallet to another and in the transaction am appending data read from a file. This is the flow:

1. First am fetching all the utxos from the sending wallet (done by the getInputs function)
2. Then I create an array of outputs (the file data and the bitcoin to transfer)

From there, I use the selectUTXO() method as directed in the documentation.

That's the flow of events in my code

[sir-stevie]

The error persists even after I exclude the output script from the code

[victorkirov]

Just took another look. I think your get utxos for address function is a bit off.

try:

async getInputs(network, fromAddress, privateKey) {
    try {
        const newPrivateKey = base58.decode(privateKey).slice(1, 33);

        // Fetch utxos to be used as inputs for this transaction 
        const firstResponse = await axios.get(`${corsProxyUrl}/${blockstreamUrl}/address/${fromAddress}/utxo`);
        const utxos = firstResponse.data;

        const inputs = [];
        
        for (const element of utxos) {
            const utxo = {
                index: element.vout,
                txid: element.txid,
                witnessUtxo: {
                    amount: element.value,
                    script: btc.p2wpkh(secp256k1.publicKeyCreate(newPrivateKey, true), network).script,
                },
            };

            inputs.push(utxo);
        }

        return inputs;
    } catch(error) {
        this.handleError(error);
        console.log("An error occurred while getting inputs");
    }
}

[sir-stevie]

The error persists, I will try debugging more see if I can come up with something