Keep IT clean - coding good practices: naming - DO OK

Keep IT clean - coding good practices: naming

This is the second post in a series of articles about broadly defined clean code. If you missed the first part of the series, which discusses comments, you can find it here.

In this post, you can learn about another factor that impacts the quality of a developer's code: naming.

I will provide a comprehensive list of dos and don'ts related to the current topic.

Good naming practices hold great significance in achieving clean code. Developers are tasked with naming nearly everything that constitutes part of the code, including packages, classes, variables, functions, and more. As you can see, this is why naming is of paramount importance for maintaining clean code. As I mentioned, I have prepared two lists. The first one is titled "DOs," and it outlines the things we should do in terms of naming. The second one, aptly named "DON'Ts," highlights the things we should avoid.


Use names that express intentions well

As the headline says, you should emphasize using names that present all of your intentions. It is not easy to choose an optimal name, but the effort devoted to it pays off in the future. Every developer, who takes a look at the author’s code written by this principle, will have a much easier task to understand it. The name of your variable, class, or method should answer these questions:

  • For what purpose is it used for?
  • What does it do?
  • How it can be used?

If it answers them, there is no need for any additional comments in the code (from a previous post you already know that in general comments are not a good idea).

Let’s assume that you want to name a variable for a distance measured in meters. Don’t call it distance, meters or m and so on. Much better will be distanceInMeters. It will give you a clear context and intentions that this variable should express. The lack of these values is a big problem.

Create names that differ clearly

It’s never a good idea to use the same or similar names for a different purpose. We are not able to see a clear difference between what is hiding below these names. Let’s take the names of methods as an example. Is naming two methods getProduct(UUID id) and getProductInfo(UUID id) a good idea? Nope, because we don’t know what is this slight difference about. We are forced to check what they are returning and what code is executing inside them. Of course, in this example, we have comfort because they are indeed returning something. If not, it would be even harder to note the difference.

Another example is using numbers for variables that have the same name, e.g. product1, product2 and so on. Although, such names are not misleading, but non-informative.

Create names that you can pronounce

Without a doubt, using mental shortcuts or a group of letters, that do not form any existing word, is sabotage in terms of clearness of code and general of the whole development process. Due to that, using the name getModStrNm for a method instead of getModifiedStreetName is not a good idea. Just imagine how funny your conversation with another dev would look if you both had to talk about this method. Not to mention the difficulty of reading and understanding the code which is still a main problem about the unpronounceable words.

Use names easy to search by

In practice, every IDE nowadays offers a search function throughout a whole project. You can search for classes, methods, variables, etc. by entering strings in the search bar. Therefore, it is another argument for not using single letters as names. Let’s assume that you called a variable with the e letter. Because it is the most-used letter in English, the results list will be huge when it comes to searching for variable e. By naming variables this way, the developer is making his life much harder.

It is a good practice to declare static variables at the top of classes. Let’s say that we make a static variable named MIN_LETTERS_PER_DAY equal to 3. Thanks to that it will be easier to find this variable with the searching feature. But there is one more reason for this practice - if it turns out that this value should be equal to 4 then all you need to do is to change 3 to 4 in one place instead of every place that this value was used.

Use verbs in method names

Methods names should be verbs or verbal nouns like activateAccount or accountActivation, period. What is more, methods that are accessors, mutators, or predicates should be created based on operated values like getExpirationTimestamp, setName and isActive.

Use one word for a concept

Developers should stick to one consistent lexicon for the project. Using different names for analogic methods in various classes is not an optimal solution. For example, you shouldn’t use get, fetch and retrieve interchangeably. These names’ meanings are slightly different, so it can cause other developers a doubt the fact that these methods are doing the same operations. So, as you can see compliance with this rule is important for the quality of our code because how your code is understandable by others is a huge factor of the final quality.

Use names of the solution and problem domains

It is a good practice to use IT terminology everywhere it is possible and reasonable. It’s because most likely everyone who will be reading our code is a developer. Whereas everywhere where there is no possibility to use IT terminology, e.g. because there is no such a name for a specific element of code, we should use a name that describes this element well in terms of a business problem that it concerns.

Add important context

Commonly, there is no possibility to name an element in any rational way in terms of giving it enough context. But with help comes a proper naming of these components which is our element (such as classes or methods). Name them in such a way so that they also could bring some needed information and somehow relieve it from a part of the responsibility of giving sufficient context. Let’s say you have the class Foo and it is responsible for something different from the method that you want to create in this class. This method will be e.g. making a real phone call using a third-party library and it will be named makePhoneCall(String from, String to). Even though the class Foo shouldn’t have any implemented methods that are not related to it at all, there is a possibility to rename it  make(String from, String to) thanks to moving it to a newly created class called PhoneCall. The class Foo could just be called something like this: PhoneCall.make(“+48123456789”, “+48987654321”) if this method was a static one of course. By the way, there is one more advantage to doing this - when you have a PhoneCall class you can divide our method’s body into a few methods to make things more clear and understandable.


Avoid disinformation

In one of the previous pieces of advice, I wrote about giving names that represent a good context. In this one, I want to warn about naming that gives a bad or unclear context. In my opinion, it is even worse than not giving the context at all. Such behavior is misinforming everyone who works with our code and even ourselves. A simple example: let’s say that you have a map that is a collection of some products. Giving this collection a name productsList is just suggesting that this collection is not a Map, but a List. This was just a simple example, but things might get more serious when you replace a name insert for a method with save.

Don’t use prefixes

If you are still using prefixes in instance variable names, then you can stop right now. After all, we are all using IDEs which can color every element of the code by its type. Thanks to that, prefixes are just useless noise in code that is worth eliminating. From my observations, I can tell that developers are ignoring these prefixes when it comes to reading such code, but why are they difficult to live with?

Avoid mental imaging

When you are writing a code you need to think not just about yourself, but also about the other developers who will or might be reading it. It is extremely important to remember that the code has to be understandable for everyone. So, according to the headline of this paragraph, don’t use any thought shortcuts or any other unclear naming that only you understand. It’s not cool to think that naming a user password variables with uP will be fine because you understand it and you will remember the meaning of this name later, while everybody else will probably have problems deduce what is this about.

Don’t use verbs in class names

This is the opposite of advice about method names. You shouldn’t use verbs in class names. Instead of them, you should use nouns or noun expressions. Also, you shouldn’t use too general names such as Parser or Generator. It would be nice to mention in these names what they can parse or generate.

Don’t be funny

Names should show their meaning well. If you make jokes, then you are darkening it and it is not transparent enough. It’s because when you make jokes, you are using some colloquialisms or slang which is not always understandable for everyone (mostly only for you or a narrow group of people).

Don’t make puns

This is analog to the advice about using one word for a concept, but the opposite way. We should always use one name only for identical operations or meanings. It will be easier to explain in an example. Let’s say that we have a few classes and there is exactly one method in each of them that does the same thing as the rest. It seems obvious that every method should have the same name. Everything is fine, but when we have to make one more class that also has to have such a method implemented and this time this method has to do a slightly different operation, we might have a problem. In this situation, it might be a temptation to name this method the same as in other classes. Unfortunately, we would do a pun, if we give up, and we want our code to be as understandable as possible and not difficult to study, right?

Don’t add too much context

In this post, I’ve already written about the necessity of adding context by properly giving the names of classes and methods. Because of that, you shouldn’t overdo it by adding too much context for elements that are a part of them. It becomes unnecessary because we already know it from the rest of the code. For example, when we have a simple DTO class UserDto, then we don’t have to use the word user in every variable name in this class. Nobody will have doubts that the variable id is the user identifier, because it already results from the context given by the name of UserDto class.


Personally, not once I came across some cases of breaking the above rules. What is interesting it was mostly when I was working on the Android projects. I think that the reason is that mobile projects are usually much smaller than the backend. It is often that only one person works on the mobile app, so he thinks that he doesn’t have to pay so much attention to the purity of the code. Unfortunately, the Android project is rarely developed from the beginning to the end by one company, and thus another developer has to face someone else’s code. I was that another developer more than once. Then I have seen some mixed names for the same elements of code, some jokes, and also a lot of dis-informative contexts. These problems are often hard to fix because they require much time to understand them first and only then you can start with refactoring.

Like in the first post, I remind you that the content of this series is based on Robert C. Martin’s Clean Code: A Handbook of Agile Software Craftsmanship book. I hope that in this post I gave you a wide and handy range of advice about naming in programming. The best would be to stick to all of them, but I think the most important thing is to remember that the code we write is not just for us, but for others as well. And with this cool conclusion, we can end this post, but before that, I would like to express my interest in your opinion. So, are there any other good or bad habits you have come across or applying to? I encourage you to think about it and share your thoughts by leaving a comment.

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