Do you have unused files, codes, and demo text on your codebase that are just lying around, taking up space and slowing down your process?
Yes, we have all been there.
A lot of things are boring and repetitive to clean up over and over again, so the simple solution is to use Knip, an automation tool for discovering unused files, exports, and dependencies.
Knip is a simple tool to use in your daily tasks. This is particularly true when projects get bigger over time, which has a detrimental effect on both maintainability and our excitement for them. Because they are usually difficult to uncover, these underutilized relics frequently go overlooked.
So where do you even begin your search for unwanted items? You’ve probably searched for a dependent globally to see if it’s still in use or use VS code.
So let’s dive into Knip and discover how it can automate this process and keep your codebase clean and lean.
What is Knip?
Knip is like a tidy-up tool for coding projects, kind of like a project cleaner. While ESLint focuses on individual files, Knip takes care of the whole project. It checks everything—files, imports, exports, and dependencies—and points out what’s not being used.
You can use Knip in two main ways. In new projects, it’s handy to install Knip early and let it grow with your code. Keep your project organized, and run Knip either manually or automatically in a CI environment.
In bigger projects, Knip is like a helpful friend for keeping things in order. It’s great at finding unused files, exports, and dependencies. There might be a few mistakes at first, but it’s much easier to ignore those than to search for unused stuff on your own.
Especially after making big changes to your code, Knip is like a cleanup assistant. It can find things you might have missed or forgotten, making it easier to keep your project neat.
Knip works with both regular JavaScript and modern TypeScript. It supports monorepos, works with any package manager, and comes with lots of features—big and small—to help you manage your projects better.
Why Choose Knip?
Detecting and removing unnecessary elements from your code is crucial, but manually identifying them is time-consuming. That’s where Knip comes in. As codebases become more complex, having an automated and comprehensive tool becomes essential.
Simplicity is Key:
Deleting unused files, dependencies, and “dead code” has several benefits:
- Easier Maintenance: Managing a project becomes simpler with less clutter.
- Improved Performance: Including unused code, files, and dependencies can negatively impact startup time, build time, and bundle size. While tree-shaking helps, it’s not a one-size-fits-all solution.
- Easier Onboarding: Newcomers to the project should be confident about the necessity of files, dependencies, and exports.
- Preventing Regressions: Similar to tools like TypeScript and ESLint, Knip checks and lints to avoid regressions by identifying forgotten files, dependencies, and exports.
Dead code negatively affects readability and should be removed to prevent unnecessary maintenance efforts.
Automation
Managing code and dependencies is often a more enjoyable task. Knip’s mission is to automate the process of finding unused elements because doing it manually is tedious and challenging. Knip uses standards and heuristics to identify delectable items; even with a few false positives, it’s faster and better than manual attempts.
Comprehensive Approach
While there are alternative tools, Knip’s advantage lies in addressing files, dependencies, and exports comprehensively. This strategy synergizes well:
- Using Plugins: Finding dependencies through plugins helps discover additional entry files, providing better coverage and insights into unused files and exports.
- Analyzing More Files: This reveals more dependency usage, refining the list of both unused and unlisted dependencies.
This approach is particularly effective in a monorepo setting where files and internal dependencies can reference each other recursively. The trade-off includes increased complexity and potentially less performance, but the benefits in completeness and correctness outweigh these concerns in the early project phase.
Greenfield or Legacy
Installing Knip in new projects keeps the codebase organized from the beginning. Integrating it into your CI workflow prevents regressions.
In large or legacy projects, Knip may report false positives and require configuration, but it can be a valuable assistant during cleanup or significant refactoring. Again, a list of results with a few false positives is more efficient than manual attempts.
Unobtrusive Integration
K-nip doesn’t introduce new syntax to learn. Unlike tools with comments like
// eslint-disable-next-line
// prettier-ignore
// @ts-expect-error
Knip avoids introducing similar comments like // knip-ignore. There are several reasons for this:
- Bug Reporting: A false positive may be a bug in K-nip, which should be reported rather than easily dismissed.
- Documentation Guidance: The documentation encourages careful consideration before using tags like @public or @internal.
- Easy Removal: If you want to remove K-nip, uninstall the dependency and delete the configuration file.
Knip v4 – What’s New
After a month-long effort, K-nip v4 brings exciting improvements, notably a streamlined process for faster runs and reduced memory usage. Throughout this period, v3 continued to receive contributions, plugins, and bug fixes.
Highlights:
Compared to v3, the key highlights of Knip v4 include:
- Performance Boost: Experience a significant speed increase, up to 80% faster runs!
- Efficient Globbing: The combination of globbing and .gitignore is now much more efficient.
- Configuration Enhancements:
- Built-in compilers for Astro, MDX, Svelte & Vue.
- Improved ignore option.
- Internal refactoring to serialize data for future enhancements like caching.
- The actual performance improvement in your projects depends on factors like size and complexity.
Major Changes
While the changes have been tested against various repositories, there may be false positives due to the major refactoring. If you encounter any, please report them!
Unused Class Members:
- Finding unused class members is now opt-in.
- Default exclusion is to prevent crashes on large repositories and to save resources for codebases that don’t use classes.
- Enable unused class members using the CLI argument or configuration option.
# Terminal windowknip --include classMembers# Configuration file{ "include": ["classMembers"]}
With this change, exploring opt-ins for other unused members like types and interfaces becomes a possibility. Enum members are still included by default.
Compilers:
- The compiler option is no longer necessary in your configuration.
- Custom compilers can remain in place, and you can revert from k-nip.ts to knip.json if preferred.
Ignore Files:
- The ignore option is used to accept patterns like examples/.
- To ignore files within a folder, update to globs like examples/**.
Upgrade to K-nip v4 for a faster, more efficient linting experience. Don’t hesitate to report any issues you encounter and explore the new opt-in features for enhanced customization.
Wrapping up
Knip stands out as a powerful automated tool designed for streamlining the detection and removal of unused files, exports, and dependencies within coding projects. With a primary focus on enhancing project maintenance and performance, Knip offers notable benefits.
Its recent iteration, K-nip v4, brings significant improvements in terms of speed, memory usage, and additional features like built-in compilers for popular frameworks. Whether you are working on a greenfield project, a large-scale repository, or a legacy codebase, proves to be a valuable assistant in keeping your codebase neat, enhancing performance, and preventing regressions.
As K-nip continues to evolve, users can look forward to an even more seamless experience in project maintenance and code optimization.
FAQs on knip
How does Knip work?
K-nip analyzes your codebase comprehensively, considering files, imports, exports, and dependencies. It automatically detects and reports unused elements, making it easier for developers to clean up their projects.
What are the benefits of using Knip?
The benefits of using K-nip include easier project maintenance, improved performance by removing unnecessary code, streamlined onboarding for new team members, prevention of regressions, and overall codebase cleanliness.
What’s new in Knip v4?
K-nip v4 introduces significant performance enhancements, including up to 80% faster runs and reduced memory usage. It also features built-in compilers for popular frameworks and improvements in configuration options.
How does Knip handle false positives?
Users are encouraged to report false positives, which may arise due to factors like missing plugins for specific tools or frameworks, configuration tweaks, or potential bugs in K-nip. The community’s feedback helps refine and improve the tool.
