nx/docs/shared/packages/eslint/enforce-module-boundaries.md

Enforce module boundaries rule

The @nx/enforce-module-boundaries ESLint rule enables you to define strict rules for accessing resources between different projects in the repository. Enforcing strict boundaries helps to prevent unplanned cross-dependencies.

Usage

You can use the enforce-module-boundaries rule by adding it to your ESLint rules configuration:

{
  // ... more ESLint config here
  "overrides": [
    {
      "files": ["*.ts", "*.tsx", "*.js", "*.jsx"],
      "rules": {
        "@nx/enforce-module-boundaries": [
          "error",
          {
            // ...rule specific configuration
          }
        ]
      }
    }
    // ... more ESLint overrides here
  ]
}

Options

Property	Type	Default	Description
allow	Array	[]	List of imports that should be allowed without any checks
allowCircularSelfDependency	boolean	false	Disable check for self circular dependency when project imports from itself via alias path
banTransitiveDependencies	boolean	false	Ban import of dependencies that were not specified in the root or project's package.json
ignoredCircularDependencies	Array<[string, string]>	[]	List of project pairs that should be skipped from Circular dependencies checks, including the self-circular dependency check. E.g. ['feature-project-a', 'myapp']. Project name can be replaced by catch all * for more generic matches.
checkDynamicDependenciesExceptions	Array	[]	List of imports that should be skipped for Imports of lazy-loaded libraries forbidden checks. E.g. ['@myorg/lazy-project/component/*', '@myorg/other-project']
checkNestedExternalImports	boolean	false	Enable to enforce the check for banned external imports in the nested packages. Check Dependency constraits for more information
enforceBuildableLibDependency	boolean	false	Enable to restrict the buildable libs from importing non-buildable libraries
depConstraints	Array	[]	List of dependency constraints between projects

Dependency constraints

The depConstraints is an array of objects representing the constraints defined between source and target projects. A constraint must include sourceTag or allSourceTags. The constraints are applied with AND logical operation - for a given source project the resulting constraints would be all that match its tags.

Property	Type	Description
sourceTag	string	Tag that source project must contain to match the constraint
allSourceTags	Array	List of tags the source project must contain to match the constraint
onlyDependOnLibsWithTags	Array	The source can depend only on projects that contain at least one of these tags
notDependOnLibsWithTags	Array	The source can not depend on projects that contain at least one of these tags
allowedExternalImports	Array	Exclusive list of external (npm) packages that are allowed to be imported
bannedExternalImports	Array	List of external (npm) packages that are banned from importing

Read more about the proper usage of this rule:

• Enforce Module Boundaries
• Ban Dependencies with Certain Tags
• Tag in Multiple Dimensions
• Ban External Imports
• Tags Allow List
• Taming Code Organization with Module Boundaries in Nx