I want to figure out if Array[] and Object[] can be replaced by Array() and Object(). Can a function prototype be stuck into arrays or objects prototype chain to make them callable. Basically I am looking for some thing like this:
// some magic with prototypes
????????????????
a = [1, 3, 4]
b = [1, 3, 4]
console.log(a[1]) // prints 3
console.log(b(1)) // prints 3
a[0] = -1
// same as
b(0, -1)
console.log(a[1], b(1)) // prints -1 -1
Thanks alot!
You probably don't want to do this, especially in any browser. This doesn't have a lot of nice features of Array, including efficiency. That said:
function ArrayFunction (arr) {
var f = function s (p, v) {
if (v !== undefined) {
s[p] = v
}
return s[p]
}
for (var i = 0; i < arr.length; i++) {
f[i] = arr[i]
}
return f
}
var a = new ArrayFunction([1, 3, 4])
var b = new ArrayFunction([1, 3, 4])
b(1, 5)
a[1] //3
b[1] //5
I originally wanted to use prototypes, but objects don't inherit callableness from their prototypes.
EDIT: Fixed above to not use arguments. This version does not allow you to set a value to undefined, but that's generally not considered a good practice anyway.
arguments are slower.
Good question but the answer is no, because objects are not functions.
The closest you can get is this:
Array.prototype.set = function(a,b) { this[a] = b; };
Then you can do:
b.set(0, -1);
() or an indexed array access [] in JS.Javascript does not support operator overloading like that. I can't think of a way to have one variable support both [] and () access, but if you don't need [] access, you could try something like:
var weird_array = (function() {
var data = [1,2,3];
return function(idx, n) {
if (arguments.length === 1)
return data[idx];
else if (arguments.length === 2)
return (data[idx] = n);
};
})();
In this example, weird_array is not actually an array, so you cannot use []'s on it, but it is a function (wrapped around a data array). You could then do:
weird_array(); // => undefined
weird_array(0); // => 1
weird_array(1); // => 2
weird_array(2); // => 3
weird_array(3); // => undefined
weird_array(1, 5); // => 5
weird_array(1); // => 5
b(0, -1)?