Event listener is giving old events

[outdoteth]

The following code is logging out events that have happened in the past.

myContract.on("someEvent", () => console.log("event"))

Expected behavior is that it logs out events only as they come in but it is logging events from 1 block in the past on initial run. I don't want to see the events from 1 block in the past - only the new events.

[shivam0x]

@Dylan-Kerler how you resolved this issue?

[AleSua93]

I ran into this same issue, anybody has a solution?

[outdoteth]

@ShivamDev31 @AleSua93 I am quite certain that it is an issue with ganache not ethersJS. Are you guys using ganache?

[AleSua93]

@Dylan-Kerler thanks for the answer! I'm using the Hardhat network... I haven't deployed anywhere else yet though, so it might certainly be an issue with the development network, but I'd have to check.

[yogh333]

Hello, I have the same issue when using ganache-cli. Are you sure that the issue comes from ganache ?

[zemse]

Can you see #1504 (comment) if that helps?

[yogh333]

Hi zemse,

Thank you for your feedback, it helped me to understand and workaround the "issue" ;)

[johnson86tw]

Temporary solution:

const startBlockNumber = await provider.getBlockNumber();

contract.on(filter, (...args) => {
  const event = args[args.length - 1];
  if(event.blockNumber <= startBlockNumber) return; // do not react to this event
  
  // further logic
})

[hickscorp]

@chnejohnson we understand that this solution filters the blocks locally - on the frontend - and only accounts for the ones emited after the startBlockNumber. As this solution visually works, it's still far from ideal from a traffic / node load point of view.
Can you think of any other solution - even monkey-patchin Ethers - that would somehow function properly?

Thanks!

[ricmoo]

You can also use:

provider.once("block", () => {
  contract.on(filter, (...args) => { ... })
});

[hickscorp]

@ricmoo this exhibits the exact same issue - with the only difference that the old events are only replayed when a new event is triggered rather than immediatelly.