Question

135

How to get Transaction Receipt Event Logs?

rated 0 times [ 142] [ 7] / answers: 1 / hits: 7348 / 2 Years ago, sun, march 6, 2022, 12:00:00

I need to get the events emitted by my smart contract and consume them in the front end via web3.

I made some event on my contract that returns event winner and ticket number:

event Winner(uint256 ticketNumber, address winner);

So I emit this event, and I see it on transaction logs.

From Etherscan:

OK! What I need is the data: ticketNumber: 1, winner: 0x........
How did I get this from web3?

Im trying to use:

 await web3.eth.getTransactionReceipt(txnHash, function (error, result) {

          console.log(result);

        });

But when I check console log, I cannot see this information, I suspect that result.logs.data is the right info, but I don't know for sure, and I don't know how to translate:

"0x00000000000000000000000000000000000000000000000000000000000000010000000000000000000000005964b608ea267bfe9ef77707fce8105a2d145e7a"

Anybody have an idea?

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answered 2 Years ago jayla · Accepted Answer

If you read the docs, there is getPastEvents method.

myContract.getPastEvents('MyEvent', {

    filter: {myIndexedParam: [20,23], myOtherIndexedParam: '0x123456789...'}, // Using an array means OR: e.g. 20 or 23

    fromBlock: 0,

    toBlock: 'latest'

}, function(error, events){ console.log(events); })

.then(function(events){

    console.log(events) // same results as the optional callback above

});

you can also create event listeners:

contract.events.Winner()

.on('data', (event) => {

    console.log(event);

})

.on('error', console.error);

Docs about subscription to events