How can I be notified when an address receives ethereum?

Question

I want to be notified when a specific account receives eth. Currently, I subscribe to ERC20 contract logs:

  web3.eth
    .subscribe(
      "logs",
      {
        address: [
          "0xabcd..." // ERC20 contract address
        ],
      },
      (err, res) => {
        if (err) console.log(err);
        if (res) console.log(res);
      }
    )
    .on("data", function (transaction) {
      console.log(transaction);
    });

which works for token transfers but not for sending eth, the callback does not get called when addresses contains my account for example.

I can subscribe to pending transactions which works when sending eth:

  web3.eth
    .subscribe("pendingTransactions", (err, hash) => {
      if (err) console.log(err);
    })
    .on("data", function (txHash) {
      return web3.eth.getTransaction(txHash, (err, returnedValue) => {
        if (err) {
          // error handling
        }
        if (
          returnedValue && returnedValue.to === accountAddress)
        ) {
          console.log(`TransactionHash: ${returnedValue.hash}`);
        }
      });
    });

however I don't know how to tell when this transaction completes, would I need another subscribe for the pending transaction hash?

Looking for a simple solution to know when a specific account receives eth using web3js, appreciate any help thanks.

Answer 1

You can subscribe to newBlockHeaders and check if the balance has changed

async function notifyBalanceUpdate(address, callback) {
    let balance = await web3.eth.getBalance(address);
    web3.eth.subscribe('newBlockHeaders')
        .on("data", async () => {
            const newbalance = await web3.eth.getBalance(address);
            if (!balance.eq(newbalance)) {
                  const oldbalance = balance;
                  balance = newbalance;
                  callback(newbalance, oldbalance);
            }
        }
    );
}

Note 1: The code doesn't account for partial modifications in one block, if several transactions modify the balance in the same block it will only notify once.

Note 2: The code doesn't take into account chain reorgs.