Stellar JS SDK listen to server streamed EventSource events

stream_listener.js

const StellarSdk = require('stellar-sdk');
StellarSdk.Network.useTestNetwork(); // StellarSdk.Network.usePublicNetwork();
const server = new StellarSdk.Server('https://horizon-testnet.stellar.org'); // const server = new StellarSdk.Server('https://horizon.stellar.org');


// convenience method: returns a PaymentCallBuilder 
// https://stellar.github.io/js-stellar-sdk/PaymentCallBuilder_PaymentCallBuilder.html#stream
// there are similar CallBuilders for other network events, this one is specific to payments
var stream = server
    .payments()
    .cursor('now')
    .stream({
        onmessage: message => {
            console.log(message)
        },
        onerror: err => {
            console.log(err)
        }
    });

// if listening for a particular event, you may want to wrap the above in a promise until the event has either occured or timed out.
// in that case, to properly close the stream, you simply call the returned function 'stream', i.e. stream()