How to handle multiple web3 transactions in nodejs

Question

I am handling a transaction like this:

web3.eth.getTransactionCount(sender_address, (err, txCount) =>{
        console.log(txCount)
        if(err){
          console.log(err);
        }else{
          const txObject = {
            nonce: web3.utils.toHex(txCount),
            to: master_address,
            value: web3.utils.toHex(web3.utils.toWei("0.1", "ether")),
            gasLimit: web3.utils.toHex(21000),
            gasPrice: web3.utils.toHex(web3.utils.toWei("10", "gwei"))
          } 

          const tx = new Tx(txObject);
          tx.sign(sender_private_key);

          const serialized_tx = tx.serialize();
          const raw = '0x' + serialized_tx.toString('hex');
          

          web3.eth.sendSignedTransaction(raw, (err, txHash) =>{
            if(err){
              console.log(err);
              
            }else{
              console.log("txHash:", txHash);
              
            }
            
          }).then(function(receipt) {
            //Insert amir
            if(receipt["status"] == true){
              console.log("Tx has been mined")
            }else{

            }
            console.log(receipt)
          });
        }

      });

At the moment this works if the sender makes 1 transaction, but if the sender makes two transactions before they are mined, the nonce is the same, and will therefore cause an error.

I have read in web3js documentation about chaining, but i am not sure if this is what i am looking for.

How would i change my existing code in order to work for multiple transactions before they are mined?

Answer 1

Your app should manage nonce and keep latest value, then use it in send transaction.

But maybe pending transactions count solve your problem

web3.eth.getTransactionCount(sender_address, 'pending', (err, txCount) =>{...