CODEWITHSUNDEEP
node.jscallbackeventemitter
user3727864
user3727864

Reputation: 41

how to remove listener from inside the callback function in node.js

I set up a listener for an event emitter and what I want to do is to remove the same listener if I get certain events. The problem I am running into is that I don't know how to pass the callback function to removeListener inside the callback function. I tried "this", but it errors out. Is there any ways to achieve this? By the way, I am not using once because I am only removing the listener on a certain event.

P.S. I am using redis here so whatever message I receive I would always be listening on the key "message". It would not be possible to just listen on different keys. Channel wouldn't help either because I only want to remove a specific listener.

Also, what I want to do is communication between two completely independent process. No hierarchy of any kind. In process B, there are many independent functions that will get data from process A. My initial thought was using a message queue, but with that I cannot think of a way to ensure that each function in B will get the right data from A.

Upvotes: 1

Views: 3341

Answers (1)

nickclaw
nickclaw

Reputation: 698

One cool thing about closures is that you can assign them a name, and that name can be used internally by the function. I haven't tested this, but you should try:

object.on('event', function handler() {
    // do stuff
    object.off('event', handler);
});

You should also look into whether your event emitter supports namespaces. That would let you do something like:

object.on('event.namespace', function() {
    // do stuff
    object.off('.namespace');
});

Upvotes: 3

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