How to stop listening to all events of contract

Question

I am using the JavaScript API in my truffle tests to get the events from the contract: https://github.com/ethereum/wiki/wiki/JavaScript-API#contract-allevents

          const allEvents = instance.allEvents({
            fromBlock: 0,
            toBlock: 'latest'
          });
          allEvents.watch((err, res) => {
            console.log(res);
          });

It never stops listening so I tried adding this to the end:

          allEvents.stopWatching()

The listening stops, but nothing is ever logged, so I tried adding a delay:

          setTimeout(allEvents.stopWatching, 1000);

But the listening doesn't stop.

How do I stop listening after all the events emitted till now have been retrieved?

Answer 1

1) Using Indexed parameters e.g address or integers can also be very useful

Examplen using ERC20.solcheck here Erc20.transfer should emit event(address _to, uint256 _amount) which can be indexed thus making it easier to filter at the front end event Transfer(address indexed _to, uint256 _amount); contract events

could be written this way, and you get events only from the indexed address and indexed amount during transfer.

Erc20.events.Transfer({ filter: { _to: recipient, _amount: amount} })
        .on("data", function(event) {
....
        }).on("error", console.error);
      }

I hope someone finds this helpful, I'm also open to correction.

Answer 2

It says that if you pass a callback function you don't need to call stopWatching(). The problem is somewhere else so just abandon the idea of using stopWatching. Could you try this implementation instead:

const allEvents = instance.allEvents({
        fromBlock: 0,
        toBlock: 'latest'
      });
      allEvents.watch((err, res) => {
        if (!error)
        console.log(res);
      });

Give me an update