Remove and add elements to functions argument list in javascript
arguments, javascript
Solution
you can "Borrow" the `shift` method from the `Array()` object like this:
cache the `shift` method
shift = [].shift;
then use it to take off the first element of the `arguments` (since it's just an array like object)
var firstArg = shift.apply(arguments); //in case you need it
.
.
.
callbacks[i].apply(callbacks[i], arguments);
and as @casablanca said,
Many methods will work with anything that behaves like an array (numeric indices and a length property)
the `shift` method is just one of them.
Problem
I have written an observer in javascript. You can trigger Events like this: ``` ClassThatExtendsEvent.triggerEvent('EventName', arg1, arg2, ..., argn) ``` There is a variable number of arguments, with the first argument being the event name. I do as well have subscribers, that are saved in a private property of my event class. They are getting called like this: ``` Event.prototype.triggerEvent = function() { var callbacks = this._events[eventName]; if(callbacks !== undefined) { for (var i = 0, l = callbacks.length; i < l; i++) { // I do not need the first argument here!!! callbacks[i].apply(callbacks[i], arguments); } } } ``` However, the subscribers do know the event name, hence it could be ommitted. But I do not know, how to remove one argument from the list (as it's not an array but seems to be some kind of object). I also need to readd the event name, once it's been deleted, because after notfiying the direct subscribers, a global event system kicks in. This global event system needs the name. Hence the entire function looks like this: ``` Event.prototype.triggerEvent = function() { // First we deliver to direct subscribers var callbacks = this._events[eventName]; if(callbacks !== undefined) { for (var i = 0, l = callbacks.length; i < l; i++) { // I do NOT need the first argument here!!! callbacks[i].apply(callbacks[i], arguments); } } // Now we broadcast the event to the entire system // I DO need the first argument here!!! Facade.getInstance().broadcastEvent.apply(Facade.getInstance(), arguments); } ``` How would you implement this?