Architecture boundaries

Architecture-boundary rules enforce import direction and module visibility between configured source-path elements (layers, features, apps in a monorepo). Every rule operates on the resolved source file of an import, relative imports are followed to the real .ts/.tsx/.d.ts file before classification. Boundary diagnostics do not offer autofixes, a violation usually needs an API or architecture decision, not a mechanical import rewrite.

Source: ported from eslint-plugin-boundaries (MIT).

• boundaries/dependencies: unified dependency-direction rule from upstream eslint-plugin-boundaries, intended to replace element-types / entry-point / external / no-private / no-unknown with a single policy block.
• boundaries/element-types: Enforce allowed dependency directions between configured source-path element types.
• boundaries/entry-point: Require imports that cross element boundaries to target the importee element’s configured public entry files (typically index.ts), so the public surface of each element is explicit.
• boundaries/external: Restrict external package imports by package or specifier pattern.
• boundaries/no-private: Reject imports of files declared private by a parent element from outside that element.
• boundaries/no-unknown: Reject relative imports whose resolved source file falls under no configured element.

// lint.config.ts
import type { ITtscLintConfig } from "@ttsc/lint";
 
export default {
  rules: {
    "boundaries/element-types": ["error", {
      elements: [
        { type: "app", pattern: "src/app/**" },
        { type: "domain", pattern: "src/domain/**", entry: "index.ts", private: "internal/**" },
      ],
      rules: [{ from: "app", disallow: "domain" }],
    }],
    "boundaries/entry-point": ["error", {
      elements: [{ type: "domain", pattern: "src/domain/**", entry: "index.ts" }],
    }],
    "boundaries/no-private": ["error", {
      elements: [{ type: "domain", pattern: "src/domain/**", private: "internal/**" }],
    }],
    "boundaries/no-unknown": ["error", {
      elements: [
        { type: "app", pattern: "src/app/**" },
        { type: "domain", pattern: "src/domain/**" },
      ],
    }],
    "boundaries/external": ["error", { disallow: ["@legacy/sdk"] }],
  },
} satisfies ITtscLintConfig;