OOP Fundamentals: The Decorator Pattern

The decorator pattern is one of my favorite patterns. It is simple, extensible and powerful. It feels like it follows the essence of object oriented programming beautifully. Sadly though, it is also easy to be misused or misunderstood. So, in this post I will show you the essence of the decorator pattern, illustrated with a few examples.

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OOP Fundamentals: The Dependency Inversion Principle

The dependency inversion principle is one of the cornerstones of object-oriented programming. Without it, there is no object-oriented design. It’s that important.

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Something out of Nothing: Null Object Pattern

What is nothing? nil? null? undefined? A vast void of emptiness that fills your soul with dread? Oh sorry, that’s just my stomach.

We often think of nothing as… well, nothing. It’s when something doesn’t exist and therefore cannot be interacted with. So in our code, we try account for having nothing. No User? No problem.

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Ruby’s Safe Navigation Operator &. and is it a Code Smell?

What is &.?

Ruby devs are probably all too familiar with seeing this error:

NoMethodError (undefined method `foo' for nil:NilClass)

Most of the time, it’s probably due to a typo, but every now and then we end up having to do something like:

defined?(bar) && bar.foo
# returns nil if bar is nil

If you’re on Rails, or are using ActiveSupport, you can use present? or try():

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Composition over Inheritance, with JavaScript examples

If you are into object-oriented programming, you most likely have heard about composition over inheritance. The concept itself is simple: Whenever possible, prefer to compose objects rather than introducing inheritance.

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Common Code Smells in OOP

Over years of reviewing Ruby code, the same things tend to come up over and over. In this post, I’d like to address some of the most common code smells I find when reviewing OOP code (and Ruby code in particular).

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Modularizing The JavaScript You Already Have

Over time, without structure, things fall apart. So give them structure, a few conventions, and start to make them more maintainable. Let me say more, at least in the context of JavaScript in your applications (or did you think I was talking about gardens or buildings or such? lol.)
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A Ruby-ish Xmas

Ruby-ish, rubbish… Get it? Anyways, not like Ruby-ish means bad! Quite the opposite!

It’s the day after Xmas and because Ruby is awesome and delivered 2.6.0, we’ll get to play with some of our new Xmas gifts: Kernel#then, Proc#>> and Proc#<<.

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Writing a Markdown Compiler – Part 3

Have you ever wanted to make your own programming language? Maybe a template engine? A JSON parser? If you have ever built any of those, you might have noticed it’s not exactly easy to get started. We’d like to help with that.

Welcome to Part 3, the final in this series on Writing a Markdown Compiler!
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