Skip to content

feat: add defineConfig helper for typed configuration files#21169

Merged
alexander-akait merged 8 commits into
mainfrom
feat/define-config
Jun 17, 2026
Merged

feat: add defineConfig helper for typed configuration files#21169
alexander-akait merged 8 commits into
mainfrom
feat/define-config

Conversation

@alexander-akait

Copy link
Copy Markdown
Member

Summary

Add a defineConfig helper (a typed identity function, like in Vite/Rollup/Rspack) so configuration files get type hints and validation without JSDoc annotations; it accepts every shape webpack-cli already loads — object, multi-compiler array, function style, and promises thereof.

What kind of change does this PR introduce?

feat

Did you add tests for your changes?

Yes — test/DefineConfig.unittest.js and test/configCases/simple/define-config{,-function,-multi-compiler}/.

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?

Document webpack.defineConfig on the configuration documentation pages.

Use of AI

This PR was implemented with Claude Code under my direction and review; I specified the design (export + types only, reusing webpack-cli's existing function-config support).


Generated by Claude Code

@changeset-bot

changeset-bot Bot commented Jun 11, 2026

Copy link
Copy Markdown

🦋 Changeset detected

Latest commit: e73a48b

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

@github-actions

github-actions Bot commented Jun 11, 2026

Copy link
Copy Markdown
Contributor

This PR is packaged and the instant preview is available (4fa6844).

Install it locally:

  • npm
npm i -D webpack@https://pkg.pr.new/webpack@4fa6844
  • yarn
yarn add -D webpack@https://pkg.pr.new/webpack@4fa6844
  • pnpm
pnpm add -D webpack@https://pkg.pr.new/webpack@4fa6844

@codecov

codecov Bot commented Jun 11, 2026

Copy link
Copy Markdown

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.72%. Comparing base (31def43) to head (e73a48b).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files
@@           Coverage Diff           @@
##             main   #21169   +/-   ##
=======================================
  Coverage   92.71%   92.72%           
=======================================
  Files         589      590    +1     
  Lines       64190    64194    +4     
  Branches    17806    17806           
=======================================
+ Hits        59514    59522    +8     
+ Misses       4676     4672    -4     
Flag Coverage Δ
css-parsing 28.70% <0.00%> (-0.01%) ⬇️
html5lib 31.17% <0.00%> (-0.01%) ⬇️
integration 88.69% <100.00%> (+<0.01%) ⬆️
test262 45.52% <0.00%> (-0.01%) ⬇️
unit 41.03% <0.00%> (-0.01%) ⬇️

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

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
  • 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

@codspeed-hq

codspeed-hq Bot commented Jun 11, 2026

Copy link
Copy Markdown

Merging this PR will improve performance by 80.34%

⚠️ 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
✅ 139 untouched benchmarks

Performance Changes

Mode Benchmark BASE HEAD Efficiency
Memory benchmark "asset-modules-inline", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}' 1,294.5 KB 221.4 KB ×5.8
Memory benchmark "side-effects-reexport", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}' 1,203.3 KB 769.5 KB +56.36%
Memory benchmark "future-defaults", scenario '{"name":"mode-production","mode":"production"}' 11.8 MB 8.8 MB +33.73%
Memory benchmark "asset-modules-bytes", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}' 320.2 KB 246.3 KB +30%
Memory benchmark "context-esm", scenario '{"name":"mode-production","mode":"production"}' 8.8 MB 7.3 MB +20.06%

Tip

Curious why this is faster? Comment @codspeedbot explain why this is faster on this PR, or directly use the CodSpeed MCP with your agent.


Comparing feat/define-config (e73a48b) with main (31def43)

Open in CodSpeed

@github-actions

Copy link
Copy Markdown
Contributor

Types Coverage

Coverage after merging feat/define-config into main will be
99.34%
Coverage Report
FileStmtsBranchesFuncsLinesUncovered Lines
bin
   webpack.js98.77%100%100%98.77%91
examples
   build-common.js100%100%100%100%
   buildAll.js100%100%100%100%
   examples.js100%100%100%100%
   template-common.js98.21%100%100%98.21%72
examples/custom-javascript-parser
   test.filter.js100%100%100%100%
examples/custom-javascript-parser/internals
   acorn-parse.js100%100%100%100%
   meriyah-parse.js100%100%100%100%
   oxc-parse.js91.30%100%100%91.30%140, 142–143, 145, 147, 153–154, 161, 168, 90
examples/markdown
   webpack.config.mjs100%100%100%100%
examples/typescript
   test.filter.js100%100%100%100%
examples/typescript-non-erasable
   test.filter.js50%100%100%50%5
examples/virtual-modules
   test.filter.js100%100%100%100%
examples/wasm-bindgen-esm
   test.filter.js100%100%100%100%
examples/wasm-complex
   test.filter.js100%100%100%100%
examples/wasm-simple
   test.filter.js100%100%100%100%
examples/wasm-simple-source-phase
   test.filter.js100%100%100%100%
lib
   APIPlugin.js100%100%100%100%
   AsyncDependenciesBlock.js100%100%100%100%
   AutomaticPrefetchPlugin.js100%100%100%100%
   BannerPlugin.js100%100%100%100%
   Cache.js98.21%100%100%98.21%101
   CacheFacade.js100%100%100%100%
   Chunk.js99.72%100%100%99.72%39
   ChunkGraph.js100%100%100%100%
   ChunkGroup.js100%100%100%100%
   ChunkTemplate.js100%100%100%100%
   CleanPlugin.js99.15%100%100%99.15%206, 226
   CodeGenerationResults.js100%100%100%100%
   CompatibilityPlugin.js100%100%100%100%
   Compilation.js98.44%100%100%98.44%1609, 1905, 1912, 1920, 1942, 2838, 3317–3318, 3350, 4014, 4044, 4097–4098, 4102, 4107, 4123–4124, 4138–4139, 4144–4145, 4622, 4648, 513, 518, 5456, 5488, 5505, 5521, 5537, 5552, 5577–5578, 5580, 5908, 5913, 5919, 5922, 5934, 5936, 5940, 5956, 5971, 6003, 6057, 6081, 6195, 763–764
   Compiler.js99.56%100%100%99.56%1135–1136, 1144
   ConcatenationScope.js98.59%100%100%98.59%189
   ConditionalInitFragment.js100%100%100%100%
   ConstPlugin.js100%100%100%100%
   ContextExclusionPlugin.js100%100%100%100%
   ContextModule.js100%100%100%100%
   ContextModuleFactory.js97.40%100%100%97.40%258, 395, 418, 420, 424, 433–434
   ContextReplacementPlugin.js100%100%100%100%
   DefinePlugin.js99%100%100%99%171–172, 188, 207, 281
   DependenciesBlock.js100%100%100%100%
   Dependency.js98.15%100%100%98.15%382, 428
   DependencyTemplate.js100%100%100%100%
   DependencyTemplates.js100%100%100%100%
   DotenvPlugin.js98.41%100%100%98.41%378, 391–392
   DynamicEntryPlugin.js100%100%100%100%
   EntryOptionPlugin.js100%100%100%100%
   EntryPlugin.js100%100%100%100%
   Entrypoint.js100%100%100%100%
   EnvironmentPlugin.js97.14%100%100%97.14%49
   ErrorHelpers.js100%100%100%100%
   EvalDevToolModulePlugin.js100%100%100%100%
   EvalSourceMapDevToolPlugin.js100%100%100%100%
   ExportsInfo.js100%100%100%100%
   ExportsInfoApiPlugin.js100%100%100%100%
   ExternalModule.js98.66%100%100%98.66%1057, 1060, 445–449, 597
   ExternalModuleFactoryPlugin.js100%100%100%100%
   ExternalsPlugin.js100%100%100%100%
   FileSystemInfo.js99.50%100%100%99.50%182, 2252–2253, 2256, 2267, 2278, 2289, 278, 3693, 3708, 3732
   FlagAllModulesAsUsedPlugin.js100%100%100%100%
   FlagDependencyExportsPlugin.js98.46%100%100%98.46%425, 434, 436, 440
   FlagDependencyUsagePlugin.js100%100%100%100%
   FlagEntryExportAsUsedPlugin.js100%100%100%100%
   Generator.js100%100%100%100%
   HotModuleReplacementPlugin.js100%100%100%100%
   HotUpdateChunk.js100%100%100%100%
   IgnorePlugin.js100%100%100%100%
   IgnoreWarningsPlugin.js100%100%100%100%
   InitFragment.js100%100%100%100%
   JavascriptMetaInfoPlugin.js100%100%100%100%
   LibraryTemplatePlugin.js100%100%100%100%
   LoaderOptionsPlugin.js100%100%100%100%
   LoaderTargetPlugin.js100%100%100%100%
   MainTemplate.js100%100%100%100%
   ManifestPlugin.js100%100%100%100%
   Module.js98.50%100%100%98.50%1285, 1290, 1350, 1364, 1426, 1435
   ModuleFactory.js100%100%100%100%
   ModuleFilenameHelpers.js98.85%100%100%98.85%106, 108
   ModuleGraph.js99.73%100%100%99.73%1005
   ModuleGraphConnection.js100%100%100%100%
   ModuleInfoHeaderPlugin.js100%100%100%100%
   ModuleNotFoundError.js100%100%100%100%
   ModuleProfile.js100%100%100%100%
   ModuleSourceTypeConstants.js100%100%100%100%
   ModuleTemplate.js100%100%100%100%
   ModuleTypeConstants.js100%100%100%100%
   MultiCompiler.js99.69%100%100%99.69%659
   MultiStats.js100%100%100%100%
   MultiWatching.js100%100%100%100%
   NoEmitOnErrorsPlugin.js100%100%100%100%
   NodeStuffPlugin.js100%100%100%100%
   NormalModule.js97.90%100%100%97.90%1240, 1243, 1260, 1277, 1524, 1558, 1574, 1661, 2017, 2316, 2321–2331, 419, 423, 577
   NormalModuleFactory.js99.47%100%100%99.47%1083, 1392, 486, 498
   NormalModuleReplacementPlugin.js100%100%100%100%
   NullFactory.js100%100%100%100%
   OptimizationStages.js100%100%100%100%
   OptionsApply.js100%100%100%100%
   Parser.js100%100%100%100%
   PlatformPlugin.js100%100%100%100%
   PrefetchPlugin.js100%100%100%100%
   ProgressPlugin.js98.85%100%100%98.85%519–520, 525, 527, 591
   ProvidePlugin.js100%100%100%100%
   RawModule.js100%100%100%100%
   RecordIdsPlugin.js100%100%100%100%
   RequestShortener.js100%100%100%100%
   ResolverFactory.js100%100%100%100%
   RuntimeGlobals.js100%100%100%100%
   RuntimeModule.js100%100%100%100%
   RuntimePlugin.js100%100%100%100%
   RuntimeTemplate.js100%100%100%100%
   SelfModuleFactory.js100%100%100%100%
   SingleEntryPlugin.js100%100%100%100%
   SourceMapDevToolModuleOptionsPlugin.js100%100%100%100%
   SourceMapDevToolPlugin.js98.62%100%100%98.62%220, 224, 226, 419, 430, 891
   Stats.js100%100%100%100%
   Template.js100%100%100%100%
   TemplatedPathPlugin.js99.17%100%100%99.17%176–177
   UseStrictPlugin.js100%100%100%100%
   WarnCaseSensitiveModulesPlugin.js100%100%100%100%
   WarnDeprecatedOptionPlugin.js100%100%100%100%
   WarnNoModeSetPlugin.js100%100%100%100%
   WatchIgnorePlugin.js100%100%100%100%
   Watching.js100%100%100%100%
   WebpackError.js100%100%100%100%
   WebpackIsIncludedPlugin.js100%100%100%100%
   WebpackOptionsApply.js100%100%100%100%
   WebpackOptionsDefaulter.js100%100%100%100%
   buildChunkGraph.js99.87%100%100%99.87%371
   cli.js98.62%100%100%98.62%10, 119, 545, 577, 627, 897
   index.js99.72%100%100%99.72%184
   validateSchema.js94.67%100%100%94.67%100, 87, 89, 98
   webpack.js96.33%100%100%96.33%10, 198, 220, 222
lib/asset
   AssetBytesGenerator.js100%100%100%100%
   AssetBytesParser.js100%100%100%100%
   AssetGenerator.js100%100%100%100%
   AssetModule.js100%100%100%100%
   AssetModulesPlugin.js97.32%100%100%97.32%281, 305, 308, 36, 360, 41
   AssetParser.js100%100%100%100%
   AssetSourceGenerator.js100%100%100%100%
   AssetSourceParser.js100%100%100%100%
   RawDataUrlModule.js100%100%100%100%
lib/async-modules
   AsyncModuleHelpers.js100%100%100%100%
   AwaitDependenciesInitFragment.js100%100%100%100%
   InferAsyncModulesPlugin.js100%100%100%100%
lib/cache
   AddBuildDependenciesPlugin.js100%100%100%100%
   AddManagedPathsPlugin.js100%100%100%100%
   IdleFileCachePlugin.js97.92%100%100%97.92%71, 83, 91
   MemoryCachePlugin.js95.83%100%100%95.83%33
   MemoryWithGcCachePlugin.js93.15%100%100%93.15%106, 113–114, 122, 89
   PackFileCacheStrategy.js96.40%100%100%96.40%1250, 1350, 1354, 1416, 628, 647, 657–659, 661, 677–678, 683, 686, 688, 693, 698, 722, 728, 762, 768, 774, 779, 790, 799, 804–805, 807, 824, 830–831, 833
   ResolverCachePlugin.js100%100%100%100%
   getLazyHashedEtag.js100%100%100%100%
   mergeEtags.js100%100%100%100%
lib/config
   browserslistTargetHandler.js100%100%100%100%
   defaults.js99.31%100%100%99.31%1439–1441, 1449, 274, 277, 282, 286
   defineConfig.js100%100%100%100%
   normalization.js99.01%100%100%99.01%191–192, 258, 273
   target.js100%100%100%100%
lib/container
   ContainerEntryDependency.js100%100%100%100%
   ContainerEntryModule.js100%100%100%100%
   

@alexander-akait alexander-akait merged commit 4fa6844 into main Jun 17, 2026
66 checks passed
@alexander-akait alexander-akait deleted the feat/define-config branch June 17, 2026 16:34
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

1 participant