LayerLens

Generates a dependency diagram in every folder of your Dart or Flutter package as Mermaid flowchart documents.

Alerts on cyclic dependencies.

NOTE: LayerLens shows inside-package dependencies. For cross-package dependencies use flutter pub deps.

Configure layerlens

Configure command globally

1. Run dart pub global activate layerlens

2. Verify you can run layerlens. If you get command not found, make sure your path contains pub cache.

Configure command for a package

1. Add layerlens: <version> to the section dev_dependencies in the package's pubspec.yaml.

2. Run dart pub get or flutter pub get for the package.

Configure IDE

To see the diagrams in your IDE:

• VSCode: install Markdown Preview Mermaid Support extension

• Android Studio: enable the "Mermaid" extension in the Markdown language settings

Generate diagrams

1. Run command:

• With global configuration: layerlens --path <your package root>

• With package configuration: dart run layerlens in the package root

2. Find the generated file DEPENDENCIES.md in each source folder, where libraries or folders depend on each other.

3. In VSCode, right click DEPENDENCIES.md and select 'Open Preview'

CI: re-generate on every GitHub push

1. Add a dev_dependency to https://pub.dev/packages/layerlens
2. Copy the content of run-layerlens.yaml to .github/workflows.

Alert on circular references

You may want to avoid circular references, because without circles:

1. Code is easier to maintain
2. Chance of memory leaks is smaller
3. Treeshaking (i.e. not including non-used code into build) is more efficient
4. Incremental build is faster

LayerLens marks inverted dependencies (dependencies that create circles) with '!'.

Also you can add command dart run layerlens --fail-on-cycles to the repo's pre-submit bots.

Build filters

If you want to generate the DEPENDENCIES.md only for a specific folders, you can use --build-filter option and you should use glob syntax. For example, to generate the diagram only for the root lib/ folder, you run following dart run layerlens --build-filter "lib".

You can specify multiple build filters . The mechanism is inspired by --build-filter in Dart's build_runner. For example, to run the layerlens for root lib/ and it's subfolder lib/subfolder1 run layerlens --build-filter "lib" --build-filter "lib/subfolder1". To generate the entire subtree for a given subfolder you can run following: layerlens --build-filter "lib/subfolder1" --build-filter "lib/subfolder1/**"

Supported languages

While layerlens concepts are language agnostic, for now only dart is supported. Please submit an issue, if you want other language to be added.

Contribute to layerlens

See CONTRIBUTING.md for details.

License

Apache 2.0; see LICENSE for details.

Disclaimer

This project is not an official Google project. It is not supported by Google and Google specifically disclaims all warranties as to its quality, merchantability, or fitness for a particular purpose.