Dependency cruiser

Validate and visualise dependencies. With your rules. JavaScript. TypeScript. CoffeeScript. ES6, CommonJS, AMD.

What's this do?

Snazzy dot output to whet your appetite

This runs through the dependencies in any JavaScript, TypeScript, LiveScript or CoffeeScript project and ...

... validates them against (your own) rules
... reports violated rules
- in text (for your builds)
- in graphics (for your eyeballs)

As a side effect it can generate dependency graphs in various output formats including cool visualizations you can stick on the wall to impress your grandma.

How do I use it?

Install it ...

npm install --save-dev dependency-cruiser
# or
yarn add -D dependency-cruiser
pnpm add -D dependency-cruiser

... and generate a config

npx depcruise --init

This will look around in your environment a bit, ask you some questions and create a .dependency-cruiser.js configuration file attuned to your project¹².

Show stuff to your grandma

To create a graph of the dependencies in your src folder, you'd run dependency cruiser with output type dot and run GraphViz dot³ on the result. In a one liner:

npx depcruise src --include-only "^src" --output-type dot | dot -T svg > dependency-graph.svg

<details> <summary>dependency-cruiser v12 and older: add --config option</summary>
While not necessary from dependency-cruiser v13 and later, in v12 and older you'll have to pass the --config option to make it find the .dependency-cruiser.js configuration file:
npx depcruise src --include-only "^src" --config --output-type dot | dot -T svg > dependency-graph.svg

</details>

You can read more about what you can do with --include-only and other command line options in the command line interface documentation.
Real world samples contains dependency cruises of some of the most used projects on npm.
If your grandma is more into formats like mermaid, json, csv, html or plain text we've got her covered as well.

Validate things

Declare some rules

When you ran depcruise --init above, the command also added some rules to .dependency-cruiser.js that make sense in most projects, like detecting circular dependencies, dependencies missing in package.json, orphans, and production code relying on dev- or optionalDependencies.

Start adding your own rules by tweaking that file.

Sample rule:

{
  "forbidden": [
    {
      "name": "not-to-test",
      "comment": "don't allow dependencies from outside the test folder to test",
      "severity": "error",
      "from": { "pathNot": "^test" },
      "to": { "path": "^test" }
    }
  ]
}

To read more about writing rules check the writing rules tutorial or the rules reference

Report them

npx depcruise src

<details> <summary>dependency-cruiser v12 and older: add --config option</summary>
While not necessary from dependency-cruiser v13, in v12 and older you'll have to pass the --config option to make it find the .dependency-cruiser.js configuration file:
npx depcruise --config .dependency-cruiser.js src

</details>

This will validate against your rules and shows any violations in an eslint-like format:

sample err output

There's more ways to report validations; in a graph (like the one on top of this readme) or in an self-containing html file.

Read more about the err, dot, csv and html reporters in the command line interface documentation.
dependency-cruiser uses itself to check on itself in its own build process; see the depcruise script in the package.json

I want to know more!

You've come to the right place :-) :

License

MIT

Thanks

Marijn Haverbeke and other people who collaborated on acorn - the excellent JavaScript parser dependency-cruiser uses to infer dependencies.
Katerina Limpitsouni of unDraw for the ollie in dependency-cruiser's social media image.
All members of the open source community who have been kind enough to raise issues, ask questions and make pull requests to get dependency-cruiser to be a better tool.

Build status

Made with :metal: in Holland.

We're using npx in the example scripts for convenience. When you use the commands in a script in package.json it's not necessary to prefix them with npx. ↩
If you don't want to use npx, but instead pnpx (from the pnpm package manager) or yarn - please refer to that tool's documentation. Particularly pnpx has semantics that differ from npx quite significantly and that you want to be aware of before using it. In the mean time: npx should work even when you installed the dependency with a package manager different from npm. ↩
This assumes the GraphViz dot command is available - on most linux and comparable systems this will be. In case it's not, see GraphViz' download page for instructions on how to get it on your machine. ↩