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Constraints prevent packages from depending on each other in ways that don’t make sense but are allowed by your package manager. They help you maintain a dependency graph that’s easy to reason about no matter how many packages are in your project. You might want to use constraints to:
  • Ensure no package can ever depend on an application
  • Ensure data packages can’t depend on ui packages
  • Ensure config packages can only depend on other config packages.

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Configuring constraints

Constraints are defined as a constraint object in your project configuration file and can be used to allow and disallow packages matching a selector. Here’s an example of a configuration that enforces the constraints above:
.commonality/config.json

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Validating constraints

You can view the status of your constraints by running the constraint command.

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Precedence

A constraint object can contain both allow and disallow constraints. When both are present, disallow constraints will be evaluated first.