If you're using something like turbolinks, phoenix_html may get loaded multiple times. This leads to a situation where users will have to click the confirm dialog over and over to get the dialog to disappear.

Looking at the code and the docs for addEventListener, I believe there should be a simple fix to this problem.

If multiple identical EventListeners are registered on the same EventTarget with the same parameters, the duplicate instances are discarded. They do not cause the EventListener to be called twice, and they do not need to be removed manually with the removeEventListener() method.

Note, however that when using an anonymous function as the handler, such listeners will NOT be identical, because anonymous functions are not identical even if defined using the SAME unchanging source-code simply called repeatedly, even if in a loop.

It looks like the root of the problem is the fact that we are using anonymous functions when adding the event listener. If we can ensure that the functions are static when the code runs again the additional event listener will be ignored since it is identical. Since this is based off behavior from rails I think it would be good to borrow/steal their implementation since it should handle these problems out of the box.

https://github.com/rails/rails/tree/master/actionview/app/assets/javascripts