Refactoring is improving or updating code without changing its external function or nonfunctional attributes. Refactoring cleans up the nonfunctional elements of software, making it easier to maintain, extend, integrate, align with evolving standards, and continue performing at acceptable speeds. It changes nothing about core functionality from the user’s perspective other than occasional cosmetic changes and improved overall performance.

Why is refactoring needed?

Writing code is somewhat like writing an article or story with a team of writers, each with their own writing style, quirks, and personal coding idiosyncrasies. Due to testing and other quality controls, this writing-by-committee approach can and does produce functioning code. However, things get messy behind the scenes. Coders take shortcuts for speed, hardcode things that shouldn’t be, and the codebase gets more brittle and bespoke over time.

This jumble of approaches may leave behind many challenges, especially for the next engineer who lifts the hood and tries to make sense of it all. Over time, these small issues accumulate, contributing to the product’s technical debt. Refactoring is one way of paying down that technical debt.

Even the best team of developers that seemingly share a single mind can’t escape the need to refactor eventually. Over time, standards change, new tools emerge, and once-beautiful code no longer runs as speedily, running the risk of becoming obsolete. Marketing and branding, supported languages, preferred terminology, and color palettes evolve. Software must reflect this evolution, even though core functionality remains unchanged.

What are the benefits of refactoring?

Refactoring is the equivalent of deep cleaning or routine home maintenance–not fun, but necessary to maintain its value, safety, and efficiency. Refactoring can lead to better user experiences, improved ability to maintain, extend and integrate, and faster performance using up-to-date standards.

Improve maintainability

What a developer hopes to find when she checks out the underpinnings of shipped software is clean, clear code, with no duplication, elegant simplicity, and few dependencies. Well-maintained code contains shorter methods and functions, fewer parameters, intuitive variable names, and minimal dependencies between classes and packages.

Achieving this state doesn’t happen by accident. It requires intentional, dedicated effort. Consequently, teams frequently place it on the back burner until issues arise.

Aside from making it easier to maintain things and fix issues that arise, refactoring also improves extensibility and integration. By having easily-understood clean code, limited features can be extended, and both internal and third-party applications can be integrated to work together more seamlessly.

While extensions and integrations don’t fall under the heading of refactoring—because the functionality is changed—it is an important precursor to being able to implement and roll those things out rapidly.

Improve performance

Performance issues impact revenue, growth, and customer satisfaction. The more convoluted the code—including unnecessary dependencies and long functions with many parameters—the more slowly that code runs over time as the underlying structure gets bogged down due to additional complexities compounded by subsequent changes.

Routinely refactoring the code by simplifying things, renaming and undoing dependencies, and breaking longer functions into shorter ones all help optimize overall performance.

Align with new standards

Last year’s cutting-edge standards age, fall out of favor and eventually become obsolete. Many standards reside in the code, so changing them often requires additional updates to align—but not fundamentally change—the functionality experienced by the user.

These changes range from swapping out an underlying component or plug-in to minor tweaks, such as a button’s color matching the new branding palette.

When is it time to refactor?

Refactoring should be built into the engineering calendar and the overall product roadmap so it gets attended to regularly. Long periods between refactoring efforts make the task even harder. The original authors may have departed the organization, taking their thinking and original rationale.

“Code smells” indicate that the code needs refactoring. Code smell examples include duplicate code, comments, long parameter lists, data clumps, unnecessary primitive variables, and dead code.

What is the role of product in refactoring?

The development team does the hands-on work of refactoring, but product management has a key role to play. Product teams must leave space in the roadmap for refactoring efforts. Furthermore, they need to engage with other stakeholders driving nonfunctional changes.

Nonfunctional changes might come from branding and marketing, including changing product or feature names, color palettes or transitioning from a more angular design aesthetic to a more smooth and rounded one. Technical dependencies may also create a need for refactoring, so product must weigh the pros and cons of delaying new features for these performance boosts and future-proofing endeavors.

How to develop a refactoring plan

When the roadmap makes space for refactoring, product, and engineering must work together on projects with the biggest returns.

Develop the scope

Refactoring accumulates many micro-refactorings–tiny changes that ripple throughout the code. Begin by figuring out the biggest issues that need tackling.

Some development environments include tools that automate searching for code smells. Other inputs to the refactoring backlog can come from customer feedback, developers on other product teams, branding, existing backlog items, and performance metrics.

Rally the team

Reach out to other stakeholders to understand what might also be on their to-do lists. Don’t forget to bring QA and testing into the planning process, as they will be key players in the initiative.

The development team will determine the methodology and techniques to use in the refactoring effort.

Test early and often

Teams must test code after each change to ensure the work achieves the desired outcome. Although frustrating for developers who want to zip through their to-do lists, this crucial step keeps bigger problems from arising downstream.

Resist the urge to squeeze in functional changes

This is not the time to sneak in bug fixes or new functionality. For a refactoring initiative to go well, save those things for later so the team can focus on improving what’s already there.

Making functional and nonfunctional changes simultaneously may introduce instability and unexpected outcomes. Teams should focus on simplicity and clarity, not chasing down brand-new bugs.

An ongoing process

The work of refactoring is never done. The very process of writing code creates debris, similar to the way a construction project creates dust and trash.

This debris must get cleaned out before it impacts functionality and performance. Technology doesn’t stand still, so organizations must return again and again to perform this essential-yet-tedious duty.