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web3.eth.subscribe Migration Guide

Breaking Changes​

New Block Headers event​

In 1.x, web3.eth.subscribe('newBlockHeaders') was used to subscribe to new block headers.

In 4.x, either web3.eth.subscribe('newHeads') or web3.eth.subscribe('newBlockHeaders') can be used to subscribe to new block headers.

web3.eth.clearSubscriptions​

In 1.x, web3.eth.clearSubscriptions returns true on success.

In 4.x, web3.eth.clearSubscriptions returns an Array of subscription ids.

// in 1.x
var subscription = web3.eth.subscribe('newBlockHeaders', function (error, result) {
    if (!error) console.log(result);
});
web3.eth.clearSubscriptions(function (error, success) {
    console.log(success); // true
});

// in 4.x
const subscription = await web3.eth.subscribe('newHeads');
subscription.unsubscribe().then(
    console.log(), // [...] Array of subsription ids
);