To add the size() method to the Array object I do:
if (!Array.size) {
Array.prototype.size = function() {
return this.length;
};
}
Is there a simple way to define the size property that will work like length ?
(I don't really need it, I just want to understand if this is something easily achievable in Javascript.)
With ES5 it's possible. Add a size property on the Array prototype,
Object.defineProperty(Array.prototype, "size", {
get: function() {
return this.length;
},
set: function(newLength) {
this.length = newLength;
}
});
var x = [1, 2, 3];
x.length // 3
x.size // 3
x.push(4);
x // [1, 2, 3, 4]
x.length // 4
x.size // 4
x.length = 2;
x // [1, 2]
x.size = 1;
x // [1]
It basically works as a wrapper around length. Appears like a property to the naked eye, but is backed by an underlying function.
Thanks to @Matthew's comment, this size property works like a complete wrapper around length.
this.length too.
I'll assume you already know this is not a real life issue.
length property is modified to suit the size of the array and reflected by methods such as shift() and pop().
So, you would need a method to get the length property.
Anurag shows you how it can be done with ES5.
if(!Array.size)
{
Array.prototype.__defineGetter__('size', function(){
return this.length;
});
}
var a = new Array();
a.push(1);
a.push(4);
console.log(a.size);
Although I'm not entirely sure how cross-browser friendly that is (should work on Chrome and FF at least).
