Know when a property has been set to an object using array notation

I have an object that is used as a hash table to store key value pairs in javascript:

Storage["key"] = "value".

I've fo开发者_Python百科und we can use defineSetter to have setters for each key, however, we need to know all key names beforehand. Is there a way of doing something whenever a value is set this way?

So for example, when doing:

Storage["key"] = "value";

I want it to be handled by a custom method like:

customMethod : function(aKey, aValue) {
  //do something with these two params
  // inform somebody else about this.
}

Thoughts/Suggestions?

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No, there isn't currently a way to catch all property assignments. Firefox 4 introduced an experimental JavaScript Proxy API which would allow you to do this (have a proxy forward all calls to an inner object but also trigger some additional action when properties are set) but it would probably be an overkill here - even if this API were stable and implemented in other browsers.

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You can override __defineSetter__ of the object to gain finer control. Caveat: Won't work in all browsers!

See this post for more details: John Resig: JavaScript Getters and Setters