How do you unwire an action in Nitrogen?

In Nitrogen, the Erlang web framework, you wire actions like this:

wf:wire(send_message, #event { type=click, postback=send_mess开发者_如何学运维age })

but if after that you run

wf:wire(send_message, #event { type=click, postback=send_message2 }),

then you get the action wired twice.

How do you unwire the previous action or all actions of an element?

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Since events in nitrogen are bound using jquery's bind method. You can use unbind to unbind them. There isn't currently a nitrogen api to unbind an event but you could output the javascript code to unbind it yourself if you so wished.

see action_event.erl for an example of how the binding javascript is output. You can create a similar action/event that removes the binding.

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I too was looking for an "unwire" and didn't find it. My work-around was to wf:replace() the element to which the event was wired, and wire the replacement element; I hope that javascript will eventually notice the former bind can never be called and then garbage collect it. I don't know how expensive such abandoned bindings are. My context was a lazy loading of the page, such that a button would initially show a stub, but when clicked would download arbitrarily large content, and henceforth toggle hide/show.

Beyond being nervous about the sophistication of the javascript garbage collection, I'm worried that this may be a bad pattern, and would love to hear others' experience. The only alternative that occurs to me would be to keep state (e.g. data) in the original element and pass that state back with the event message so that the same event handler would act on the "unloaded->loaded_show->loaded_hide->loaded_show" transitions. But I'd prefer not to be calling back to the server for a simple hide/show transition.