How can I find EventSource running? get the EventSource instance that exists?

[huudatk53]

I using nodejs, I create new EventSource(url) then add listEventsoure variable and call onmessage.
If I foreach listEventSource and call item.close(). All event close.
And I clean listEventsoure ( not call method close). But onmessage still working.
Is there an id to identify the generated event source object?
How can I find, check EventSource exists and close it.