Barrel files

Overview

Barrel files (e.g., index.ts) re‑export from multiple modules for ergonomic imports. They can hurt tree‑shaking and create cycles. Debarrel rewrites imports that target a barrel file into direct imports from source files at build time (best for dev/test speed and tree‑shaking)

Debarrel

Rewrites import { X } from "./components" to import { X } from "./components/X" (based on re‑exports) during transform.

Enable via Packem config (built-in):

import { defineConfig } from "@visulima/packem/config";

export default defineConfig({
  rollup: {
    debarrel: {
      // include: [/\.([cm]?tsx?|jsx)$/],
      // possibleBarrelFiles: [/index\.(t|j)sx?$/],
    },
  },
});

Notes:

• Targets TS/JS and JSX variants; you can further scope via include
• Works purely at build time; no runtime overhead

Tests

See integration tests under packages/packem/__tests__/intigration:

• barrel.test.ts (general barrel usage)