Web3 - can ETH transaction be cancelled? - node.js

Question

I am trying to create a website where ethereum transaction can be made.
If I make an eth transaction using eth.sendTransaction({from:sender, to:receiver, value: amount}) can this transaction be cancelled?
I am asking this because I see that it doesn't take any promise or callback parameters, meaning I would have no idea whether the transaction has been made successfully or not?
Is it possible for web3 transactions to be cancelled? and if it is, how do I make sure that I get notified whether transaction has been made or not? (preferrably using promises or callback rather than having to check wallet every time)

Answer 1

It’s technically possible to cancel a transaction, but highly unlikely. Essentially, the only way to do so would be to try to send another transaction using the same account/nonce combination and hope it gets mined before the transaction you want to cancel is mined. It’s merely a side effect of how nonce is used to guarantee transaction order rather than a cancellation feature.
For your other question, web3.eth.sendTransaction does take a callback. It’s an optional second parameter after the options object and uses the error/result callback style. From the Web3js API:
web3.eth.sendTransaction(transactionObject [, callback])
Function - (optional) If you pass a callback the HTTP request is made asynchronous.
Using callbacks
If you want to make an asynchronous request, you can pass an optional callback as the last parameter to most functions. All callbacks are using an error first callback style

Answer 2

To cancel some ethereum pending transaction you need to:
Create a new transaction where you will send 0 ETH to yourselves.
You should increase the value of gas fees
You need to use the same nonce of the pending transaction.
Using web3js you can do something like this:
async function main() {
require('dotenv').config();
const { API_URL, PRIVATE_KEY } = process.env;
const { createAlchemyWeb3 } = require("#alch/alchemy-web3");
const web3 = createAlchemyWeb3(API_URL);
const myAddress = //put your address
const nonce = //put the nonce of pending tx
const maxFeePerGas = //increase the gas fee value comparated to the pending tx
const transaction = {
'to': myAddress,
'value': 0,
'gas': 21000,
'maxFeePerGas': maxFeePerGas,
'nonce': nonce
};
const signedTx = await web3.eth.accounts.signTransaction(transaction, PRIVATE_KEY);
web3.eth.sendSignedTransaction(signedTx.rawTransaction, function(error, hash) {
if (!error) {
console.log("The hash of your transaction is: ", hash);
} else {
console.log(error)
}
});
}
main();