Knip
Knip is an open-source tool that identifies unused files, exports and dependencies in JavaScript and TypeScript projects, including monorepos.
Why it caught my attention
Unused code is surprisingly difficult to spot once a project grows beyond a handful of files. Knip looks across the project rather than checking individual files in isolation, making it possible to uncover redundant modules and dependencies that conventional linting may not identify.
What problem does this actually solve?
Knip could be worth considering if you recognise any of these challenges.
Old files remain in projects
Files left behind after changes make projects harder to navigate. Knip identifies files that appear unused.
Unnecessary dependencies accumulate over time
Packages may remain installed long after their last use. Knip helps identify dependencies that could be removed.
Unused exports create maintenance clutter
Functions, types and other exports can outlive their consumers. Knip highlights exports that appear to have no users.
Large repositories complicate code cleanup
Multiple packages make usage difficult to trace manually. Knip analyses relationships across supported monorepo workspaces.
Is this a good fit for you?
A quick way to see if Knip is relevant for your situation.
- You maintain JavaScript or TypeScript applications with growing codebases.
- Your team regularly removes features or refactors existing modules.
- You want to identify unnecessary packages in project dependencies.
- You work with multiple packages in a monorepo.
- You want automated checks for unused code during development.
- Your projects primarily use languages outside JavaScript and TypeScript.
- You only need conventional linting for variables within individual files.
How does it work?
In practice, the workflow looks something like this:
Install Knip through your JavaScript package manager or run it without installing, then start an initial analysis of your repository.
Knip detects supported frameworks and tools. Adjust entry points, workspace settings or exclusions where its defaults do not match your project.
Knip follows references between project files and reports unused files, exports, dependencies and other issues based on the resulting analysis.
Investigate reported issues, correct missing references and remove confirmed unused code. Optional automatic fixes can handle supported changes after review.
Run Knip again after cleanup or include it in development workflows to identify newly unused code and dependencies.
What else should I know?
A few important things to be aware of before you investigate further.
JavaScript and TypeScript focus
Knip targets JavaScript and TypeScript ecosystems, although plugins and compilers extend analysis to supported framework file formats.
Project configuration affects accuracy
Missing entry points, dynamic imports or unsupported conventions can produce misleading findings. Review configuration before deleting reported code.
Automatic fixes require careful review
Knip can modify exports and dependencies, with optional file deletion. Use version control and test changes before accepting them.
Open-source licensing and runtime requirements
Knip is free under the ISC licence. Version 6 requires Node.js 20.19.0 or later on supported branches, or Bun.
Think Knip could fit your environment?
Visit the Knip website to find out more, request a demo or speak to their team.
Something you'd like to know about Knip?
Is there something I haven't covered in my research? Send me your question and I'll look into it and reply personally by email.