4

There are two ways to subscribe/watch to logs/events:

Subscribe:

var subscription = web3.eth.subscribe('logs', {
    address: '0x123456..',
    topics: ['0x12345...']
}, function(error, result){
    if (!error)
        console.log(log);
});

Unsubscribe:

subscription.unsubscribe(function(error, success){
    if(success)
        console.log('Successfully unsubscribed!');
});

But how do I unsubscribe if I watch the logs / events like this:

myContractWebsocket.events.MyLogName({
    filter: {'orderId': '0x123456...'}, 
    fromBlock: 0
    })
    .on('data', data => { console.log(data); })
    .on('error', error => { console.log(error); });

2 Answers 2

1

Struggled with this as well, here is my solution:

Event Setup

let subscriptionId;
const eventEmitter = web3.contract.events.MyEvent({...options})
   .on('connected', id => subscriptionId = id)
   .on('data', event => {
      // Your event logic
    })

Unsubscribe

// Unsubscribe if connected successfully and not undefined
if(!subscriptionId) return
eventEmitter.options.requestManager.removeSubscription(subscriptionId)
0

myContractWebsocket.events.MyLogName returns a Subscription response, which has an unsubscribe method. See here for a bit more detail.

2
  • Unfortunately it doesn't work like that. I get TypeError: subscription.unsubscribe is not a function
    – Rob Magier
    Feb 17, 2019 at 18:26
  • @RobMagier could you add the code from attempting this answer, along with the error, into the question? Jan 7, 2021 at 10:41

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