What is code documentation?

Code documentation is the process of adding descriptive text and visual elements to software code to explain its purpose, functionality, and structure. It helps developers understand, maintain, and update the code with ease, fosters collaboration and knowledge sharing among team members, and enhances code usability.

Code documentation can take various forms, such as:

Explanations of code functions and blocks
Providing clear descriptions of how individual functions and code blocks work.
Comprehensive developer handbooks
Including dos and don'ts, summaries of every aspect of the application, and other useful information.
Illustrative images
Such as sequence and entity relationship diagrams, to help visualize the code's structure and relationships.
API documentation
Describing each class, method, argument, and return value for developers who interact with the code.
ReadME files
Providing an overview of the codebase and instructions for getting started.

The benefits of good documentation

Improved Understandability

Good documentation helps developers, including yourself, understand the purpose, functionality, and structure of the code.
Faster Onboarding
When new developers join a project, well-documented code accelerates their onboarding process. They can quickly grasp the code's architecture and how different components work together.
Enhanced Collaboration
It helps developers communicate about code, share knowledge, and work together more efficiently.
Maintenance and Debugging
Well-documented code makes it easier to identify and fix bugs, as it provides insight into the behavior and logic of the code.
Reduced Dependence on Original Developers
Code documentation makes it easier for others to work on, modify, or maintain the code without relying heavily on the original developer.
Enhanced Code Reusability
Well-documented code is more likely to be reusable in other parts of the project or in different projects, saving time and effort.
Code Reviews
Documentation makes it easier to conduct code reviews, as reviewers have a clear understanding of the code's purpose and expected behavior.

Types of documentation

There are several types of code documentation that you can consider. Here are some of them:

Process documentation
Describes the processes and procedures used in software development, such as project management, testing, and deployment.
Planning documentation
Includes project plans, schedules, and budgets.
Estimate documentation
Provides estimates of the time and resources required to complete a project.
Standards documentation
Describes the coding standards and guidelines used in a project.
Metrics documentation
Includes metrics such as code coverage, test results, and performance data.
Design documentation
Describes the design of the software, including architecture, data models, and user interfaces.
Code comments
Comments within the source code that explain how the code works, what it does, and why it is there.
Technical reports
Detailed reports that describe the technical aspects of the software, such as algorithms, data structures, and performance.
Walkthrough documentation
Provides a detailed description of a software system's source code, including the purpose of each code module, the inputs and outputs of functions, and any assumptions or constraints that the code relies on.

Common mistakes to avoid in documentation

No Documentation
Leaving your code without any explanations is a big mistake. It makes it hard for others, including your future self.
Outdated Documentation
If your code changes, your explanations should too. Make sure your documentation stays current.
Complex Comments
Keep your comments short and clear. Long, complicated comments can make the code harder to read.
Unclear Names
Choose clear names for your variables and functions. Confusing names make the code harder to understand.
Missing Examples
Show how to use your code with examples. It helps people understand it better.

Documentation best practices

Here are the software documentation best practices to consider:

Write clear and concise

1. Use easy-to-understand language that both seasoned and novice developers can understand.
2. Avoid using too much technical jargon and complicated explanations.
3. Find the right balance between under-documentation and over-documentation.
Clearly state the intent and functionality of the code
1. Use comments to explain why the code is there
2. Use comments to explain how the code works.
Update your documentation continuously
1. Keep your documentation up-to-date as you make changes to your code.
2. Delete dead documentation that is no longer relevant.
3. Use version control to track changes to your documentation.
Use Documentation as Code (DaC)
1. Write documentation as part of your code
2. Use tools that allow you to generate documentation from your code.
Plan and organize your documentation
1. Use headers, subheadings, and sections to organize your material.
2. Divide longer documents into logical sections or modules for easy navigation.
3. Use tables and diagrams to illustrate complex concepts.
Provide references and links
1. Include references to outside sources, such as specifications or design papers.
2. Include links to relevant resources whenever possible.
3. Use glossaries to define technical terms and concepts.

Documentation tools for developers

Static site generators
1. Jekyll, Hugo, and Sphinx are some of the most common authoring and publishing tools used in docs-as-code scenarios.
2. Docusaurus is a code documentation tool for a documentation website, and it has received positive feedback from users.
Documentation generators
1. Swagger, Redoc, and Stoplight are common documentation of code generators used for API documentation.
2. Doxygen is a tool that can be used to generate documentation from code.
3. Exhale is an automatic C++ library API documentation generator that uses Doxygen, Sphinx, and Breathe.
Annotation libraries
1. Code annotation libraries like go-swagger, Springfox, or NSwag can be used to add API-specific metadata to your source code, which can then be used to generate simple reference documentation.
Sphinx
1. Sphinx is a powerful documentation tool that supports output to HTML using template themes and to LaTeX/PDF using LaTeX templates.
2. The javasphinx-apidoc utility can be used to automatically generate Java domain restructured text documents from the Javadoc HTML to be compiled into the Sphinx documentation.

The future of code documentation

AI-Assisted Documentation
AI tools make documentation faster and more accurate. They can even generate code explanations from the code itself, reducing manual work.
Docs-as-Code Approach
This approach treats documentation as part of the code, stored together and managed with version control. It encourages teamwork among developers, writers, and others to review and update documentation easily.
Integration with Development
Documentation tools now work alongside development processes. Some can automatically create docs from code comments or notes.

To conclude

Good code documentation enhances collaboration, improves understandability, and reduces dependence on original developers. There are several types of code documentation, including process documentation, planning documentation, etc.

To create effective documentation, follow best practices such as writing clear and concise documentation, updating your documentation continuously, using Documentation as Code (DaC), and planning and organizing your documentation. There are several tools available for documentation, including static site generators, documentation generators, annotation libraries, and Sphinx.

The future of code documentation includes AI-assisted documentation, the Docs-as-Code approach, and integration with development workflows.

By following these best practices and keeping up with the latest trends and tools, you can create documentation that is accurate, comprehensive, and easy to maintain.

Code Documentation: The Go-To Guide