Absolutely, you’ve nailed the core use case here—barrel files (those index.js/index.ts files you’re creating) are absolutely designed to hide a subfolder’s internal file structure from parent modules, while letting the subfolder’s own files use direct relative paths freely. Let me break this down clearly:

1. Hiding internal structure from parent folders #

This is one of the most common and powerful reasons to use barrel files. Here’s how it works:

• Suppose you have a components subfolder with Button.js, Card.js, and Modal.js.
• Instead of making parent files import from ./components/Button or ./components/Card, you create a components/index.js that exports all these files:

  export { default as Button } from './Button';
  export { default as Card } from './Card';
  export { default as Modal } from './Modal';
  

• Now parent modules only need to import from ./components directly:

  import { Button, Card } from './components';
  

• The big win here? If you later rename Modal.js to Dialog.js, or add a new Input.js component, you only need to update the barrel file—all parent imports stay exactly the same. The parent folder never has to know about the subfolder’s internal file changes.

2. Using direct relative paths within the subfolder #

You’re also correct that inside the subfolder, you can (and should) use direct relative paths to reference specific files. For example:

• In components/Modal.js, you can directly import a utility from ../utils/helpers.js or even a sibling component like ./Button.js if needed.
• There’s no requirement to go through the barrel file for internal references. In fact, using direct paths is often better here—it keeps dependencies explicit, avoids potential circular imports (if the barrel file references files that reference it back), and makes it clearer exactly which modules a file depends on.

Extra note: Keep barrels focused #

To get the most out of barrel files, only export the modules that are meant to be used outside the subfolder. Avoid exporting internal utility files that no parent module needs to know about—this keeps your public API clean and prevents unnecessary bundle bloat (modern bundlers like Webpack or Vite can tree-shake unused exports, but it’s still good practice).

内容的提问来源于stack exchange，提问作者darkwing