eslint-plugin-code-import-patterns

This plugin can be used to allow/forbid specific import specifiers in certain areas ("zones") of the codebase.

It is inspired by the code-import-patterns rule used at microsoft/vscode (see microsoft/vscode/.eslintrc.json#L93). Actually, this plugin is based on their custom implemented rule, but was extended to allow custom error message and regexes.

It can be used to:

• enforce code layering in the codebase
• allow the usage of NodeJS built-in modules (e.g. path) only in certain code areas
• ...

Configuration

Since the rule uses JavaScript regexes for the zones target parameters, the rule can currently only be used in ESLint JavaScript configurations (.eslintrc.js).

If you need support for JSON/YAML configurations, feel free to reach out by creating an issue!

module.exports = {
  // ... eslint configuration
  plugins: ["code-import-patterns"],
  rules: {
    "code-import-patterns/patterns": [
      "error",
      {
        zones: [
          {
            target: /\/src\/ui\/.+/,
            allowedPatterns: ["react", "react-dom"],
          },
        ],
      },
    ],
};

See the examples below and ./src/types.ts for how to configure the patterns rule.

Examples

Allow dayjs to be imported in the entire codebase:

{
  zones: [
    {
      target: /.+/,
      allowedPatterns: ["dayjs"],
    },
  ],
}

Allow react and react-dom to be imported in src/ui:

{
  zones: [
    {
      target: /\/src\/ui\/.+/,
      allowedPatterns: ["react", "react-dom"],
    },
  ],
}

Given a directory components-library which has its components exposed via a index.js (or index.ts) file, forbid code in src/ui to reach into the internals of components-library:

{
  zones: [
    {
      target: /\/src\/ui\/.+/,
      forbiddenPatterns: [
        {
          pattern: /\/components-library\/[A-Z].+/,
          errorMessage:
            'Prefer to just import from "components-library" instead of reaching for the component files.',
        },
      ],
    },
  ],
}

Enforce the entire codebase to import icons from components-library/icons.tsx instead of importing them directly from a JS package:

{
  zones: [
    {
      target: /\/src\/ui\/components-library\/icons\.tsx$/,
      allowedPatterns: [/^@mui\/icons-material/],
    },
    {
      // use a negative lookahead to exclude components-library/icons.tsx from this zone
      target: /\/src\/ui\/(?!components-library\/icons\.tsx)/,
      forbiddenPatterns: [
        {
          /**
           * A RegExp can be used to match the import pattern.
           * This is especially helpful when dealing with packages which have a slash in their package name (scoped packages).
           */
          pattern: /^@mui\/icons-material/,
          errorMessage:
            "Don't import from @mui/icons-material directly. Import the icon from component-library/icons.tsx instead. If the icon in question is not present in icons.tsx yet, add the icon there. (putting all icons in icons.tsx makes it easier to modify them in the future)",
        },
      ],
    },
  ],
}