Web3.js does not include extra data with the function?

Question

I encountered a problem where the included hex data is not visible on the blockchain. Here's the code snippet I used:

const tx = {
    from: wallet.address,
    to: to,
    chainId: 44445,
    value: web3.utils.toHex(web3.utils.toWei(amount, 'ether')),
    gasLimit: web3.utils.toHex(21000),
    gasPrice: web3.utils.toHex(web3.utils.toWei('21', 'gwei')),
    nonce: nonce,
    data: '0x' + stringToHex(qtmtransactionType)
};

The issue arises when I send a transaction with this code. Despite including hex data in the data field, it doesn't seem to appear on the blockchain.

You can find an example transaction on the blockchain through this link

I've double-checked the code and the provided Explorer link, but I'm unable to identify why the hex data isn't visible on the blockchain. Any insights or suggestions on how to resolve this issue would be greatly appreciated. Thank you!

Answer 1

If you're using web3.js version 4.6.0 (i.e., the latest available version at this point in time), then when you prepend '0x' to stringToHex("any string message"), you might encounter this error when passing it as data to the transaction:

Error: Cannot convert string to Uint8Array. only supports 0x-prefixed hex strings and this string was given: 0x0x...

Because stringToHex() already includes the '0x' prefix, so there's no need to prepend it explicitly.

Also, you might need to calculate the gasPrice and gasLimit, because passing these values as static, might result in the reverting of transaction. Since, you're passing data along with the transaction, so the expected gasPrice and gasLimit for the transaction to be included in the block would change according to the data length and complexity (also depending on certain other factors like network/chain that you're using, network congestion, etc.).

Therefore, the right approach would be to calculate both of these values using the corresponding web3.eth functions, i.e., web3.eth.getGasPrice() and web3.eth.estimateGas.

Here is a sample code to test the same end-to-end:

const { Web3 } = require('web3');
const { stringToHex } = require('web3-utils');

const providerUrl = 'JSON_RPC_PROVIDER_URL';
const web3 = new Web3(providerUrl);

// Example transaction parameters
const fromAddress = 'SENDER_ADDRESS';
const toAddress = 'RECIPIENT_ADDRESS';
const privateKey = 'SENDER_PRIVATE_KEY';
const amountToSend = web3.utils.toWei('0.1', 'ether'); // 0.1 ETH
const data = stringToHex('Hello, World!'); // Convert string to hexadecimal

// Get current gas price
web3.eth.getGasPrice()
    .then(gasPrice => {

        // Estimate gas limit
        web3.eth.estimateGas({
            from: fromAddress,
            to: toAddress,
            value: amountToSend,
            data: data
        })
            .then(gasLimit => {

                // Create the transaction object
                const txObject = {
                    from: fromAddress,
                    to: toAddress,
                    value: amountToSend,
                    gas: gasLimit, // Gas limit
                    gasPrice: gasPrice, // Gas price
                    data: data // Include data in the transaction
                };

                // Sign the transaction
                web3.eth.accounts.signTransaction(txObject, privateKey)
                    .then(signedTx => {
                        // Send the signed transaction
                        web3.eth.sendSignedTransaction(signedTx.rawTransaction)
                            .on('transactionHash', (hash) => {
                                console.log('Transaction hash:', hash);
                            })
                            .on('receipt', (receipt) => {
                                console.log('Transaction receipt:', receipt);
                            })
                            .on('error', (error) => {
                                console.error('Transaction error:', error);
                            });
                    })
                    .catch(error => {
                        console.error('Signing error:', error);
                    });
            })
            .catch(error => {
                console.error('Error estimating gas limit:', error);
            });

    })
    .catch(error => {
        console.error('Error fetching gas price:', error);
    });