Return Null? Think Twice!

What does everyone’s code uglier? Actually, the only thing is code itself. Unnecessary code. The code that would not be written if the author of library I use thought about me, but not about his awesomeness.

Checks before foreach

What do I mean? I used to spend lots of time for writing code like this:

if ($news->hasCategories()) {
    foreach ($news->getCategories() as $category) {
        // Do some stuff

Okay, at least there is hasCategories function. But wait… Why do I need this if wrapper? Why library author does not just return empty array instead of null if there is no category? Do not be that guy :)

Default values

Another way to uglify your code is:

{% if project.logo %}
    <img src="{{ project.logo.path }}" />
{% else %}
    <img src="/path/to/default.png" />
{% endif %}

Looks pretty familiar, isn’t it? What’s wrong with this piece of code? How can I make it better?

First of all, define __toString() function for Logo to return path and shorten this piece: {{ project.logo }}.

The second thing will allow us to get rid of the whole construction. Martin Fowler calls this refactoring “Introduce null object”. Project::getLogo() should return an instance of tiny class that represents default value. And this object will return /path/to/default.png. This instance can be anonymous if it is possible in language you use (no way in PHP).

<?php // Project.php
class Project 
    /** @return LogoInterface */ 
    public function getLogo() {
        return $this->logo ?: new DefaultLogo();
<?php // DefaultLogo.php
class DefaultLogo implements LogoInterface
    public function path() {
        return '/path/to/default.png';
    public function __toString {
        return $this->path();

And now our glue code is that simple:

<img src="{{ project.logo }}" />

Yes, this refactoring creates more complex library code, but significantly reduces amount of high-level glue code. That is awesome for me, I hate glue code :)


When you write some code, think of a guy who will use your code in his work. Probably, this guy is you.

Alex Panshin avatar
About Alex Panshin
Software Engineer from Russia. Interested in PHP, Scala, microservices and Big/Fast Data stuff.
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