As a software developer, you may be familiar with the feeling of apprehension that comes with adding a feature or fixing a bug in one of your company’s legacy code files. This feeling arises because you know it may take more time to relearn and understand what the code is doing than to add your new solution. You also may have experienced a time in the past where you’ve added a quick fix that ended up introducing a new bug in another area, since the code has multiple complex functionalities all dependent on each other.

These are common characteristics of legacy code. The original code written by previous developers has been added onto over the years, resulting in a potentially large code file filled with complexities that may result in confusion. Determining where to add your feature or where the bug may originate from can be time-consuming and frustrating.

Some may argue you should abandon the file all together and start completely fresh. This may seem like a good option; however, your legacy code contains numerous crucial customizations that are essential to your business. Missing or losing any part of these customizations is not worth starting from scratch. You can instead take the time to modernize the code and make it easier to debug the next time you need to add to it.

Although there are many potential approaches to working your way to a more modern codebase, I will offer three simple strategies on how this can be done.

Convert to modular functions

The first strategy is to create modular functions wherever possible. Separating your code into modular pieces will allow you to reuse your functions in multiple places. In many cases, you may already have multiple code snippets in place that have a similar function. By converting the code into one central function, you can keep all the related logic together and, in the future, you’ll only need to update the logic once. This reduces duplication and helps you to maintain a cleaner codebase.

Some software development techniques you can use include coupling and cohesion. Coupling is how dependent a function or module is on other objects or functions, while cohesion is how related the code is within a function. Ideally, you want high cohesion and low coupling. For example, a code file with high cohesion and low coupling has multiple independent modular functions that allow variables to be passed in and that aren’t dependent on any other processes or functions.

A monolithic codebase can be problematic because updating one area may result in many other areas being affected. By writing modular functions, you will be able to add new features or fix bugs with greater ease, as there will be fewer places the functionality will touch. It also makes programming in tandem easier, as two developers can each work on separate functions at the same time without affecting the other’s work. This avoids blocking any member of your team, because they won’t need to wait for your work to be completed.

Write readable code

Another strategy is writing readable code snippets. When you open a legacy code file, you may notice it is hard to read because the variables aren’t descriptive, or the logic is so complex that it takes too much time to understand what each code snippet is doing.

Even if you were the original author of the code, it can be difficult to get back up to speed if it is not readable enough. Taking the time to convert and write readable code allows your team to be able to go back later and quickly interpret the code’s functionality. This can be achieved in many ways, such as following your company’s style guidelines and using descriptive variables.

At Synergex, some of our software development teams have implemented style guidelines to maintain consistency and make the code easy to scan through. A few examples are setting maximum character line limits in our IDEs (Visual Studio Code, Visual Studio, etc.), enforcing variable naming conventions, and organizing variables by type. These style guidelines have helped our team on numerous occasions to be able to read through a code file and spend less time determining where a solution should go. My team, the Information Systems team, has also started adding documentation blocks to every code file we update. These comment blocks give more context to the functions and variables in the code, which further helps us to be more efficient and productive.

Creating variables with descriptive names is another way to write more readable code. This allows the whole team to know what the variable is intended for and how it is being used in the greater scheme of the function. Being as descriptive as possible, but not too complex, is key. For example, a variable intended to hold the first name of the user might be called firstName, instead of just name. Using firstName helps to differentiate the variable from another variable you may use, such as lastName for the last name of a user.

Clean unused code

The final strategy I will offer is to clean up any functionally unused code. There may have been times in the past where a feature was removed from your codebase, but not all its parts were eliminated in the process. Or maybe there was a feature in development that was never completed and is not necessary to the overall flow of your application, but it remains in the code.

As you take the time to understand the code you are working on, it’s important that if you find code that is no longer being used, you remove it. Removing the old code as well as adding the feature you are working on not only cleans up the codebase, it also helps you clearly see how necessary the remaining parts are. Ultimately, your future self and future developers will thank you.

Conclusion

In the end, it’s essential to the overall health of the business that your codebase be readable and easy to interpret, especially since you may not be the one who needs to debug it in the future. And it’s important to learn from your frustrations with legacy code. When you go to create a new code file, add a new feature, or fix a bug, you should use the strategies outlined above to leave the code better than you found it. Taking the time to offer a clean, robust solution will save you and your team valuable time and effort in the future.