Sandbox::https://github.com/unjs/unimport/pull/574

haigou-web · 2026-10-07T12:21:20Z

Fixes #541

Problem

export default class Foo {} was always imported as a named import:

import { MyClass } from './foo'   // should be: import MyClass from './foo'

mlly's findExports() returns two entries for that source — a default one and a declaration one, both starting at the same offset. scanExports() added a default import plus a named import plus a type import, and then dedupeImports() kept the wrong one: the correct {name: "default", as: "MyClass"} was dropped in favour of {name: "MyClass", as: "MyClass"}.

Note this is specific to class: export default function foo() {} yields only the default entry, which is why the two behave differently.

Fix

The declaration branch now skips entries that came from an export default statement, so only the default import survives. The type import is kept — MyClass is valid as a type, which is what mlly's change was for.

Verification

New test/default-class.test.ts
Before the fix the new test fails with the exact output from the issue (expected 'import { MyClass } from ...' to contain 'import MyClass from')
Full suite compared against a stashed baseline: the only difference is the new test flipping; the 11 pre-existing Windows snapshot failures are identical
tsc --noEmit: exit 0; eslint: exit 0

Summary by CodeRabbit

Bug Fixes
- Default-exported classes are now imported correctly when used without an explicit import.

coderabbitai · 2026-10-07T12:21:35Z

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults
Review profile: CHILL
Plan: Advanced
Run ID: a28f30c8-25b6-479f-9d30-957d6a89cc43

📥 Commits

Reviewing files that changed from the base of the PR and between bbd0776 and 355aa0e.

📒 Files selected for processing (2)

src/node/scan-dirs.ts
test/default-class.test.ts

Included review availability: This review used your included allowance. Your plan provides up to 4 included reviews per hour; 2 remain after this review.

📝 Walkthrough

Walkthrough

scanExports no longer adds a named value import for declarations reported from export default code. A regression test verifies that import injection uses a default import for a default-exported class.

Changes

Default class import correction

Layer / File(s)	Summary
Handle default-exported declarations `src/node/scan-dirs.ts`, `test/default-class.test.ts`	`scanExports` omits named value imports for declarations whose code starts with `export default`. The test checks that injection uses `import MyClass from` and not a named import.

Priority: ➖ Normal

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix · Severity of issue fixed: Medium

Suggested reviewers: flo0806

Merge Risk: ⚪ Minimal · up to 355aa

The default-exported class is now injected with default-import syntax. No actionable merge risk remains in this change.

Architecture Summary

Architecture risk: 🔵 Low · up to 355aa

The change affects 2 systems.

Changed systems: src, test

Architecture concerns
No architecture-level concerns identified.

Review details

Systems and components

observed — src (service) was modified; 1 changed file maps to changed impact.
observed — test (service) was modified; 1 changed file maps to changed impact.

Before / after behavior

observed — Modified behavior in src/node/scan-dirs.ts: toImport now detects declarations whose code starts with export default and omits their named value imports, while retaining reserved-word filtering and subsequent type-import handling. Other declarations continue to produce named value imports.
observed — Modified behavior in test/default-class.test.ts: Adds imports and test setup that creates a temporary directory and default-exported class file before the test, then removes the directory afterward.
observed — Modified behavior in test/default-class.test.ts: Adds a test that scans the class file and verifies import injection uses import MyClass from and does not use a named import for MyClass.

🚥 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%. Docstring coverage is scoped to functions touched by this diff. Analyzed 2 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Issue `#541` requires `export default class MyClass` to produce a default import, not a named value import. In `src/node/scan-dirs.ts`, `scanExports()` now skips the value import for declaration entries…
Out of Scope Changes check	✅ Passed	The reported changes are limited to `scanExports()` behavior and a regression test for the `export default class` case in issue `#541`. Both changes directly support the linked issue. The whole diff cou…
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main fix for importing `export default class` declarations correctly.

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haigou-web · 2026-10-22T13:50:32Z

Friendly note: the Unit Test workflow on this PR is sitting in �ction_required, so no checks have actually executed yet. Could a maintainer approve the run when convenient? I'll address anything it surfaces.

Fix export default class being imported as a named import

355aa0e

haigou-web changed the title ~~Fix export default class being imported as a named import~~ fix: import export default class declarations correctly Oct 8, 2026

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fix: import `export default class` declarations correctly - #574

fix: import `export default class` declarations correctly#574
haigou-web wants to merge 1 commit into
unjs:mainfrom
haigou-web:fix/default-class-import

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haigou-web commented Oct 7, 2026 •

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