Not able to retrieve callback parameters - callback

Question

var arr = [1,2,3,4,5,6];
Array.prototype.filter2 = function(){
var fir = arguments[0];
var sec = arguments[1];
alert(fir);
alert(sec);
var arr2 = new Array();
for(var item=0; item<this.length;item++){
alert(this[item]); // 1 section
if(sec.call(this[item],fir)){
arr2.push(this[item]);
}
}
return arr2;
}
function xyz (ele ,x){
alert(x);
alert(ele);
return ele > x;
}
arr.filter2(2,xyz);
Till 1'st its running fine but while passing the argument to the callback... x is being alerted as "undefined" whereas ele = fir

Answer 1

Your answer is simple and straight:
either call your function normally,.. i.e
Array.prototype.filter2 = function(){
var fir = arguments[0];
var sec = arguments[1];
alert(fir);
alert(sec);
var arr2 = new Array();
for(var item=0; item<this.length;item++){
alert(this[item]); // 1 section
if(sec(this[item],fir)){
arr2.push(this[item]);
}
}
return arr2;
}
Or if you still want to stick with javascript .call(), then simply use it like this:
Array.prototype.filter2 = function(){
var fir = arguments[0];
var sec = arguments[1];
alert(fir);
alert(sec);
var arr2 = new Array();
for(var item=0; item<this.length;item++){
alert(this[item]); // 1 section
if(sec.call({},this[item],fir)){
arr2.push(this[item]);
}
}
return arr2;
}
call() and apply() are predefined JavaScript function methods. Both methods can be used to invoke a function, and both methods must have the owner object as first parameter.
You can read more about this by clicking here and find it under heading Invoking a Function with a Function Method