JS function returning another function
- by Michael
I want to understand about variables, that has been used in returning function.
This is example code
Prototype = {}
Prototype.F =
{
bind: function()
{
var args = arguments, __method = args.shift(), object = args.shift();
return function()
{
return __method.apply(object, args.concat(arguments));
}
}
}
function ObjectA()
{
...
this.addListener = Prototype.F.bind(this.eventSource.addListener,
this.eventSource);
...
}
var a = ObjectA();
a.addListener(this); // assuming 'this' here will point to some window object
As I understand the returning function in F() is not evaluated until it's called in the last line. It's ok to accept. So addListener will hold a function body containing 'apply'.
But what I don't understand, when addListener is called, what kind of parameters it is going to have? particularly _method and args will always be uninitialized?
