Cross browser Leading Zeros with JavaScript

This is a short entry for further reference

Left padding an integer with zeros was never so easy. Can't believe this ended up working.

function LeadWithZeros(num, pad) {
    return (Array(pad).join('0') + num).slice(-pad);
}

LeadWithZeros(5, 3) === '005';
LeadWithZeros(65, 3) === '065';
LeadWithZeros(120, 3) === '120';

!isset, is_null, empty: The Good, the Bad and the Ugly

Hi everyone, you programmers trying to grasp the intricacies of PHP. As coders, our raw material is, and will be, information and knowledge. But lack of knowledge does not give us some information, too? Is of this absence that we will discuss today: How to know if we don't know something in PHP. And our main tools are isset, is_null and empty. Want to know more about them? Which one is The Good, The Bad and The Ugly?

Exchanging currencies with Zend_Currency_CurrencyInterface

As many companies offering online services do, we handle multiple currencies. This often involves querying external services to know the real value of the currency exchange. Previously, this logic was scattered all over the code, even copy-pasted in multiple files, and is pretty hard to mantain, let alone to test.

So, in my work detecting and extracting patterns from old spaghetti code, I came with the following solution: A Service layer.

How to detect if a class implements an Interface?

I'm in the real need to know if, given a string className or object, it implements a particular interface. I'm specially interested in the string className part.

During the search, many seemingly valid options appeared: instanceof, is_subclass_of, is_a, ReflectionClass::ImplementsInterface, class_implements… Which one to use? Let's do some testing!