The Tenets of Clean Code

In the last chapter, we discussed the purpose that sits at the very beginning of a piece of code: solving a problem for a user. We discussed the difficulties of catering to both the machine and the human. We reminded ourselves that, at its core, writing code is about communicating intent.

In this chapter, we will derive four core tenets from those foundations that are necessary to think about when creating software. These tenets are reliability, efficiency, maintainability, and usability. A good piece of software can be said to have all of these qualities. A bad piece of software can be said to have none of them. Crucially, however, these tenets are not rules. Instead, it is useful to see them as lenses through which you can look at your code. For each tenet, we will discover why it is important through a mix of analogies and JavaScript examples. You should...

Reliability

Reliability is the core underpinning of a good software system. Without reliability, the usefulness of technology quickly dissipates, leaving us in a position where we may have been better going without it. Technology's entire purpose can be undermined by unreliability.

Reliability, however, is not only a characteristic of large and complex software systems. Each and every line of code can be constructed to be either unreliable or reliable. But what do we mean by this? Reliability, the word, refers to the quality of being reliable. What does it mean to write code that people can rely on? It helps by defining reliability in terms of three distinct qualities: Reliability is the quality of being correct, stable, and resilient.

Correctness

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Efficiency

We live in a world of scarcity. Resources are finite. In order to write the best possible code, we need to take this scarcity into account. So, when designing and implementing our ideas, we should be doing so with an eye toward efficiency.

In this section, we'll explore the different facets of efficiency and tie them into the world of JavaScript through examples. Hopefully, you will come away with an appreciation for how efficiency is not only about going fast but that it encompasses many indirect effects, spanning the gamut from economy to ecology.

Time

One key scarcity that we are always aware of is time. Time is a vital resource that we should seek to only spend with due consideration. In the world of programming...

Maintainability

Maintainability is the ease with which appropriate changes can be made to your code. Unlike a motor vehicle, code does not typically need routine maintenance to avoid things such as rust, but it does, nonetheless, need to be fixed from time to time. Changes to its functionality are also often required, especially when under active development. Much of the code we work on is also being actively worked on by others. This shared ownership relies heavily on the tenet of maintainability.

Making code maintainable should not be a sidelined priority. It is as vital as any other requirement that the code is fulfilling. In the first chapter, we spoke a lot about the importance of considering who your users are. It would be disingenuous not to see that those who maintain and make changes to our code are also our users. They wish to wield what we have created to fulfill a...

Usability

While maintainability is predominantly about catering to other programmers, usability is about catering to all users, whoever they may be. We can say that there are two broad groups of users that are engaged in our service:

• People wishing to wield the power of our code via interfaces (GUIs, APIs, and so on)
• People wishing to make changes to our code to accomplish new tasks or fix bugs

Usability is about making our code, and the functions and interactions it enables, as useful and easy to use as possible for the full gamut of users. All code is written with at least one use case in mind, and so it is fair to judge code based on the extent to which it fulfills that purpose. Usability, however, goes further than this. Usability is not only about fulfillment of user requirements; it's about creating experiences that enable a user to achieve their goals with minimal...

Summary

In this chapter, we've explored the vital tenets of reliability, efficiency, maintainability, and usability. Using these tenets as lenses through which we can look at our code bases ensures that we will be far more likely to write cleaner code. One of the most important things we've learned in this chapter is always to consider the human in the code we write. The user may be a human sitting on the other side of a GUI or a fellow programmer making use of our APIs. Either way, being constantly aware of this human is vital.

In the next chapter, we'll continue the theme of studying the underlying characteristics of clean code by looking at the enemies to be aware of, such as cargo-cult programming and ego.