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feat: inline const for default export#21189

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alexander-akait merged 7 commits into
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feat/inline-const-default-export
Jun 24, 2026
Merged

feat: inline const for default export#21189
alexander-akait merged 7 commits into
mainfrom
feat/inline-const-default-export

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@hai-x

@hai-x hai-x commented Jun 15, 2026

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Summary

What kind of change does this PR introduce?

We already inlines named const exports (optimization.inlineExports) but explicitly skipped export default <const> (the template carried a "For now we don't set inlined value for export default expression" note). This makes a default export inlinable when its expression is a primitive constant.

Did you add tests for your changes?

Yes

Does this PR introduce a breaking change?

No

If relevant, what needs to be documented once your changes are merged or what have you already documented?

n/a

Use of AI

Yes

@changeset-bot

changeset-bot Bot commented Jun 15, 2026

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🦋 Changeset detected

Latest commit: b5b947e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package
Name Type
webpack Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

@codecov

codecov Bot commented Jun 15, 2026

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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.81%. Comparing base (2e43eb4) to head (b5b947e).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files
@@           Coverage Diff            @@
##             main   #21189    +/-   ##
========================================
  Coverage   92.80%   92.81%            
========================================
  Files         590      592     +2     
  Lines       64647    64801   +154     
  Branches    17993    18057    +64     
========================================
+ Hits        59996    60142   +146     
- Misses       4651     4659     +8     
Flag Coverage Δ
css-parsing 28.71% <10.00%> (+0.01%) ⬆️
html5lib 31.19% <10.00%> (+0.06%) ⬆️
integration 88.96% <100.00%> (+0.04%) ⬆️
test262 45.41% <65.00%> (+0.01%) ⬆️
unit 41.48% <10.00%> (+0.09%) ⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

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@codspeed-hq

codspeed-hq Bot commented Jun 15, 2026

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Merging this PR will not alter performance

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 5 improved benchmarks
❌ 2 regressed benchmarks
✅ 137 untouched benchmarks

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

Mode Benchmark BASE HEAD Efficiency
Memory benchmark "side-effects-reexport", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}' 128.3 KB 859.3 KB -85.07%
Memory benchmark "css-modules", scenario '{"name":"mode-development","mode":"development"}' 860.3 KB 1,676.2 KB -48.68%
Memory benchmark "asset-modules-bytes", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}' 1,043.2 KB 320.3 KB ×3.3
Memory benchmark "css-modules", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}' 1,150.3 KB 411.1 KB ×2.8
Memory benchmark "many-chunks-esm", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}' 330.4 KB 164 KB ×2
Memory benchmark "many-modules-commonjs", scenario '{"name":"mode-production","mode":"production"}' 9.1 MB 7.4 MB +23.83%
Memory benchmark "context-esm", scenario '{"name":"mode-production","mode":"production"}' 9.2 MB 7.7 MB +20.57%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.


Comparing feat/inline-const-default-export (b5b947e) with main (efeb5ce)

Open in CodSpeed

@neoncube2

neoncube2 commented Jun 15, 2026

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I'm excited for this! :D

(Although I suppose that Terser might already inline the default export)

@hai-x

hai-x commented Jun 18, 2026

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Let's merge #21199 first, and then come back to this.

@hai-x hai-x force-pushed the feat/inline-const-default-export branch from cdb5dd9 to a50ad94 Compare June 23, 2026 08:39
@github-actions

github-actions Bot commented Jun 23, 2026

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This PR is packaged and the instant preview is available (ef03f5e).

Install it locally:

  • npm
npm i -D webpack@https://pkg.pr.new/webpack@ef03f5e
  • yarn
yarn add -D webpack@https://pkg.pr.new/webpack@ef03f5e
  • pnpm
pnpm add -D webpack@https://pkg.pr.new/webpack@ef03f5e

@hai-x hai-x marked this pull request as ready for review June 24, 2026 07:08
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Types Coverage

Coverage after merging feat/inline-const-default-export into main will be
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@alexander-akait alexander-akait merged commit ef03f5e into main Jun 24, 2026
68 checks passed
@alexander-akait alexander-akait deleted the feat/inline-const-default-export branch June 24, 2026 08:15
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3 participants