how I can get the transaction hash before web3.eth.sendSignedTransaction

[dk-lan]

        let tx = new Tx(rawTransaction);
        tx.sign(privateKey);
        let serializedTx = '0x' + tx.serialize().toString('hex');
        // I need to get the transaction hash here
        let sender = web3.eth.sendSignedTransaction(serializedTx).once('transactionHash',  async hash => {
            console.log(hash)              
        })

[OFRBG]

You might want to try this: https://web3js.readthedocs.io/en/1.0/web3-eth-personal.html#signtransaction

[dk-lan]

You might want to try this: https://web3js.readthedocs.io/en/1.0/web3-eth-personal.html#signtransaction

tq for you reply, but I only have privateKey, signtransaction must need password for account.

[OFRBG]

Managing plaintext private keys is a bad idea, but if you must, then try with https://web3js.readthedocs.io/en/1.0/web3-eth.html#signtransaction.

[dev1644]

@dk-lan This will get you the txHash of your transaction before sending it.
const txHash = await web3.utils.sha3(serializedTx);

[dk-lan]

@dev1644
thanks , the way is correctly

[mmo2112]

@dev1644, hi I've tried wtih online hashing such as https://emn178.github.io/online-tools/keccak_256.html but the result is different. Maybe web3 has modified few input data or something? Thanks for your help so much bro.