EventStream api only return new transactions

Question

As mentioned in Following payments using EventStream I am able to receive the payment stream on the server side, now what if I want to return only new trisections from the time I start the stream? Is that possible?

var EventSource = require('eventsource');
var es = new EventSource('https://horizon-testnet.stellar.org/accounts/GB7JFK56QXQ4DVJRNPDBXABNG3IVKIXWWJJRJICHRU22Z5R5PI65GAK3/payments');
es.onmessage = function(message) {
    var result = message.data ? JSON.parse(message.data) : message;
    console.log('New payment:');
    console.log(result);
};
es.onerror = function(error) {
    console.log('An error occured!');
}

Answer 1

Yes. Add the parameter cursor=now to your request.

If you expect it may be in the future or the very recent past, you can run two streams (concurrently or in serial if you like), one with cursor=now&order=desc & consume events until you've found your expected payment or the timestamp is too early. And another with cursor=now&order=asc to check for future payments.

See the documented arguments.

Answer 2

As pointed out by the "Warning" on the page, you may consider switching to using the official JS SDK:

var lastCursor = "now"
var accountAddress = GB7JFK56QXQ4DVJRNPDBXABNG3IVKIXWWJJRJICHRU22Z5R5PI65GAK3

var es = server.transactions()
  .forAccount(accountAddress)
  .cursor(lastCursor)
  .stream({
      onmessage: txHandler
  })

lastCursor="now" gives you only new coming messages. You may try with using other values for lastCursor, other than zero (which will push out all the related info since the start of the chain).