如何删除使用闭包添加的EventListener？

Question

This is basically a followup question to this: Can't pass event to addEventListener: closure issue .

I have read almost every related question and can't find the answer to this.

The function below is executed within a loop where the parameters are pulled from an array of data. With this function I am able to pass different/new parameters to each instance of an event listener. The outerfunction allows for the values of the parameters to be encapsulated within closure so that the actual values are available, not just references to the holders. Additionally, the passeventfunction passes the event to the responsefunction. Finally, the responsefunction has all the appropriate info in order to respond to the click event. This works great. The problem is, I can't figure out how to remove the event listener at a later time. I have tried everything that I can think of. Please help. How can I: removeEventListener ?

(function outerfunction(i, f) {
     elementname.addEventListener("click", function passeventfunction(e) { 
         responsefunction(e, f, i); });})(parameter1, parameter2);

also, if someone could help clear up what is happening here. Is this a closure within a closure? Is there a danger of leaving a memory leak or something?

Answer 1

You have to keep references to your listeners:

var listeners = {};
for(/* ... */) {
   (function outerfunction(i, f) {
        var listener = function(e) { 
            responsefunction(e, f, i); 
        }
        elementname.addEventListener("click", listener);
        listeners[elementname.id] = listener; // use something meaningful 
                                              // as your keys
   })(parameter1, parameter2);
}

// Removing the listener later:
elementname.removeEventListener("click", listeners[elementname.id]);