Have you extended a Native lately? It's an incredibly helpful thing.
The Difference:
I've seen stuff like this:
fn1(fn2(10, fn3('house')));
Hard to figure out what's happening. Instead you can write code like:
fn3('house').fn2(10).fn1();
A Useful, Real Example, zeroPad
I've used this in a couple scripts, it takes a number and returns a string with zeros padded in front: 123 becomes '000123'. Really handy for filenames and the like.
Functionally Based Example
function zeroPad(num, zeros){
zeros = zeros || 3;
var str = '' + num;
zeros.times(function(){ str = '0'+str; });
return str;
};
// usage
doSomething(zeroPad(document.getElementById('myInput').value, 3));
Native Extentions Based Example
Number.implement({
zeroPad: function(zeros){
var str = '' + this;
zeros.times(function(){ str = '0'+str; });
return str;
}
});
// so that it works on both numbers and strings
String.implement({
zeroPad: function(zeros){
return this.toInt().zeroPad(zeros);
}
});
// usage
$('myInput').get('value').zeroPad(3).doSomething();
Side by Side:
doSomething(zeroPad(document.getElementById('myInput').value, 3));
// vs
$('myInput').get('value').zeroPad(3).doSomething();
Awesome? Yes.
Some say extending natives is a bad idea. Personally, I think it's awesome--but this topic is a sore spot for some.
Flippin' Sweet Array methods
Arian Stolwijk created this amazing gem: Array.Math . Code samples often tell the story faster:
[2,5,1,6].sum(); // 14
[2,5,6,2].product(3); // [6,15,18,6]
[9,12,15].quotient(3) // [3,4,5]
This is all made possible by extending the
Array
native, see?
Array.implement({
sum: function(start,length){
var sum = 0,
start = start ? start : 0,
length = length ? length : this.count()-start;
length = start ? length + 2 : length;
for(var i=start;i<length;i++) sum += this[i];
return sum;
},
product: function(p){
var arr = $type(p) == 'array';
return this.map(function(entity,i){
return arr ? (entity * p[i]) : (entity * p);
});
},
quotient: function(q){
var arr = $type(q) == 'array';
return this.map(function(entity,i){
return arr ? (entity / q[i]) : (entity / q);
});
},
// and a whole lot more awesome ...
});
Quick Tips
-
this
is the number or string, or whatever, when inside the method. -
Return something that makes sense (usually
this
). - You can implement several methods all in the same code block.
This is just one more great tool to help keep your code organized and readable.