Aim for simplicity over complexity. This applies to everything from overarching architectural decisions down to function implementations.
This principle is a close cousin of the previous one – aim for clear, readable code – but emphasises one particular aspect of what makes code clear and readable: simplicity.
Simpler solutions tend to be easier to implement, to maintain, to reason about and to discuss with colleagues and clients.
It can be tempting to think that for software to be good or valuable it must be complicated. There can be an allure to complexity, I think partly because we tend to equate hard work with good work. So if we write something labyrinthine and hard to understand, it’s tempting to think it must also be good. But this is a false instinct when it comes to software. In code, hard does not equal good. In general complexity for its own sake should be avoided. It’s important to remember that there’s absolutely nothing wrong with a simple solution if it does what’s needed.
There’s also value in getting a simple solution working quickly so that it can be demoed, reviewed and discussed early compared to labouring for a long time over a complex solution that might not be correct. Something we emphasise a lot working at 67 Bricks is the value of iteration in the agile process. It can be extremely powerful to implement a basic version of a feature, site or application so that stakeholders can see and play with it and then give feedback rather than trying to discuss an abstract idea. Here, simplicity really shines because often getting a simple thing in front of a stakeholder in a week can be a lot more valuable than getting a complicated thing in front of them in a month.
This principle applies at every level at which we work, from designing your architectural infrastructure, down through designing the architecture of each module in your system, down to writing individual functions, frontend components and tests. At every level, if you can achieve what you need with fewer moving parts, simpler abstractions and fewer layers of indirection, the maintainability of your whole system will benefit.
Of course there are caveats here. Some code has to be complicated because it’s modelling complicated business logic. Sometimes there must be layers of abstraction and indirection because the problem requires it. This principle is not an argument that code should never be complicated, because sometimes it is unavoidable. Instead, it is an argument that simplicity is a valuable goal in itself and should be favoured where possible.
Another factor that makes this principle deceptively tricky is that it is the system (the architecture, the application, the class etc) that should be simple, not necessarily each individual code change. A complex system can very quickly emerge from a number of simple changes. Equally, a complicated refactor may leave the larger system simpler. It’s important to see the wood for the trees here. What’s important isn’t necessarily the simplicity of an individual code change, but the simplicity of the system that results from it.
There’s also subjectivity here: what does “simple” really mean when talking about code? A good example of an overcomplicated solution is the FizzBuzz Enterprise Edition repo – a satirical implementation of the basic FizzBuzz code challenge using an exaggerated Enterprise Java approach, with layers of abstraction via factories, visitors and strategies. However, all the patterns in use there do have their purpose. In another context, a factory class can simplify rather than obfuscate. But it’s important not to bring in extra complexity or indirection before it’s necessary.