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fix: add missing type for default class exports#542

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ilyaliao:fix/default-class-dts
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fix: add missing type for default class exports#542
ilyaliao wants to merge 1 commit into
unjs:mainfrom
ilyaliao:fix/default-class-dts

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@ilyaliao

@ilyaliao ilyaliao commented May 25, 2026 •
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This PR adds the missing type for export default class X so the generated d.ts surfaces default as X in the type re-export block. Without it, X is only registered as a value and cannot be used as a type.

Source:

// classes/Foo.ts
export default class Foo {}
export class Bar {}

Before:

declare global {
  const Bar: typeof import('./classes/Foo').Bar
  const Foo: typeof import('./classes/Foo').default
}
// for type re-export
declare global {
  // @ts-ignore
  export type { Bar, Foo } from './classes/Foo'
  import('./classes/Foo')
}

After:

declare global {
  const Bar: typeof import('./classes/Foo').Bar
  const Foo: typeof import('./classes/Foo').default
}
// for type re-export
declare global {
  // @ts-ignore
  export type { default as Foo, Bar } from './classes/Foo'
  import('./classes/Foo')
}

waiting on unjs/mlly#354 to be merged

Summary by CodeRabbit

  • Improvements
    • Enhanced export scanning so export default class ... is recognized and correctly reflected in generated type declarations.
  • Tests
    • Updated inline snapshots to cover the new default class export handling and ensure consistent declare global output.

@coderabbitai

coderabbitai Bot commented May 25, 2026 •
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Review Change Stack

📝 Walkthrough

Walkthrough

The PR adds detection for default-exported class declarations in scan-dirs.ts. A new regex constant identifies export default class patterns, and the export scanning logic conditionally emits a type-only import entry when a default export matches this pattern. A playground fixture and test snapshots verify the behavior.

Changes

Default-exported class detection

Layer / File(s) Summary
Test fixture for default-exported class
playground/composables/DefaultClass.ts		 A new module exports an empty DefaultClass as a default export to serve as test subject.
Default-exported class detection and type-only import emission
src/node/scan-dirs.ts		 Introduces regex RE_DEFAULT_CLASS_EXPORT to recognize export default class syntax and extends scanExports to emit a type-only import entry when the default export is a class.
Test snapshot updates for class export detection
test/scan-dirs.test.ts, test/dts.test.ts		 Snapshots verify detection behavior: scanDirExports expects both a value export and a type-only class export entry for DefaultClass, and dts snapshots include DefaultClass in global constants and type re-export logic.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

A class exported by default takes flight,
But type-checking needs it held tight—
The regex catches what must be known,
So imports of types stay cleanly shown. 🐰✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name Status Explanation Resolution
Docstring Coverage ⚠️ Warning Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Write docstrings for the functions missing them to satisfy the coverage threshold.
✅ Passed checks (4 passed)
Check name Status Explanation
Title check ✅ Passed The title 'fix: add missing type for default class exports' accurately summarizes the main change: adding proper type support for default class exports in generated d.ts files.
Linked Issues check ✅ Passed Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check ✅ Passed Check skipped because no linked issues were found for this pull request.
Description Check ✅ Passed Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing Touches
🧪 Generate unit tests (beta)
  • Create PR with unit tests

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@codecov

codecov Bot commented May 25, 2026

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Codecov Report

❌ Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 94.28%. Comparing base (a4a5e0a) to head (ff39068).
⚠️ Report is 172 commits behind head on main.

Files with missing lines Patch % Lines
src/node/scan-dirs.ts 66.66% 1 Missing ⚠️
Additional details and impacted files 
@@            Coverage Diff             @@
##             main     #542      +/-   ##
==========================================
- Coverage   98.73%   94.28%   -4.45%     
==========================================
  Files          14       15       +1     
  Lines        1817     1033     -784     
  Branches      374      341      -33     
==========================================
- Hits         1794      974     -820     
- Misses         23       54      +31     
- Partials        0        5       +5

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@ilyaliao @claude
fix: add missing type for default class exports
27c5c0f 
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
@ilyaliao ilyaliao force-pushed the fix/default-class-dts branch from ff39068 to 27c5c0f Compare June 16, 2026 15:05
@ilyaliao ilyaliao marked this pull request as draft June 16, 2026 15:22
@GrantGryczan GrantGryczan mentioned this pull request Jun 16, 2026
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@ilyaliao