Just as a reminder: If you participated in the error tracking challenge and haven’t yet mailed your results to me, please do so ASAP. The address is jani at codeutopia net I will be posting some results next week.
What is a null object, and when are they useful?
If you’ve written code, you’ve probably used the value null to indicate some variable is not set. This is perfectly good, but did you know there’s more to nulls than just the value null? There is also a null object, which doesn’t really have anything to do with the value null, but its purprose is similar. How many times have …
Improving code with peer reviews
Peer reviewing is the practice of looking at code written by others to find errors or ways to improve the code. Sometimes also called desktop reviewing, this approach can be useful for various reasons: If you have a coworker who is more experienced than you, you can learn from him/her It’s often helpful to have another set of eyes take …
What makes an abstraction good, and why should I care?
You probably know what abstraction means – making a complex process simpler – but do you know what makes an abstraction good, and why it’s important? If you are writing code for a project that lives a bit longer, or has multiple developers working on it, having a good abstraction matters. Lack of a good and consistent abstraction will reduce …
Reader challenge: Keep track of code errors
The book Code Complete suggests to keep track of common mistakes. This is so that you can see what mistakes you make most often, and so that you can have a checklist of things that you should check when debugging. I want to challenge you, dear reader, to keep track of your mistakes with me for the coming three weeks. …
Using canvas to do bitmap sprite animation in JavaScript
Have you ever thought about writing a game? If you have, you’ve probably wondered how to render animations for your game characters. In this post, I’ll show you how you can use JavaScript to do time-based sprite animations, drawing them on canvas – vital if you want to do a game. You can also apply the same techniques I’ll show …
Unit-testing essentials
Here’s some essential unit-testing posts I’ve written recently. While some of them have examples in PHP, they should still be useful in other languages as well. Unit testing PHP series Unit testing introduction Writing and running tests Writing tests for exsisting code Mock Objects and testing code which uses the database Test-driven development General testing topics Unit-testing JavaScript How to …
How to make your code testable
Image by Jim Frazier I’ve recently been working on a code-base which wasn’t designed with test-driven development methodologies, or with unit testing in mind. As I implemented unit-tests to this code, there were some modifications I had to do on the code. Some modifications popped up more than others. There were a few things that are more common than others …
Unit testing JavaScript
I’ve recently been looking into some JavaScript unit testing frameworks. There are many alternatives, and while many of them seem good, very few of them actually matched my requirements: Must be able to run tests from the commend-line Tests should be relatively easy to write
Weekend coding: Add a character counter as the background of a textarea with JavaScript
Have you ever filled a textarea on a page, which had a limit to how many characters you could type into it? Or maybe you are a Twitter user, and as you know, Twitter only displays 140 characters of your tweets. (Not an actual textarea) The other day I was thinking of this: How to effectively communicate how many characters …