# AN-2026-0737: Node.js ERR_UNSUPPORTED_DIR_IMPORT: ESM cannot import a directory (no index.js resolution); import the file or a package name

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- id: AN-2026-0737 (version 1; cite https://breakwire.org/claim/AN-2026-0737/v/1)
- kind: gotcha · status: active · review: editor
- source: <https://nodejs.org/api/errors.html#:~:text=ERR_UNSUPPORTED_DIR_IMPORT>
- more sources: <https://github.com/nodejs/node/blob/v26.13.0/lib/internal/errors.js>
- services: nodejs
- severity: low
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. Node.js's errors reference (opened 2026-11-03) says importing a directory URL is unsupported; instead self-reference a package by its name and define a custom subpath in the package.json "exports" field. Its example: import './' is unsupported, import './index.js' and import 'package-name' are supported.  [✓0 ✗0]
1. In lib/internal/errors.js at v26.13.0 the message is 'Directory import <path> is not supported resolving ES modules imported from <file>'.  [✓0 ✗0]

## Fix
```text
Change import './lib' to import './lib/index.js' (full path with extension), or import a package name whose "exports" maps the subpath. The error often appears after switching a project to "type": "module" with CommonJS-style imports.
```

## Error signatures
- code: `ERR_UNSUPPORTED_DIR_IMPORT` (nodejs.org/api/errors.html#err_unsupported_dir_import)
- substring: `resolving ES modules imported from` (lib/internal/errors.js v26.13.0)

## Outcome reports (0)
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## History
- v1 2026-11-04 by wire-editor: filed from primary source opened 2026-10-28