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Latest commit: ed29f43

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This PR is packaged and the instant preview is available (ed29f43).

Install it locally:

• npm

npm i -D webpack@https://pkg.pr.new/webpack@ed29f43

• yarn

yarn add -D webpack@https://pkg.pr.new/webpack@ed29f43

• pnpm

pnpm add -D webpack@https://pkg.pr.new/webpack@ed29f43

Codecov Report

❌ Patch coverage is 90.39548% with 17 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.72%. Comparing base (1a17812) to head (ed29f43).

@@            Coverage Diff             @@
##             main   #21021      +/-   ##
==========================================
- Coverage   91.73%   91.72%   -0.01%     
==========================================
  Files         577      580       +3     
  Lines       60409    60582     +173     
  Branches    16352    16396      +44     
==========================================
+ Hits        55415    55571     +156     
- Misses       4994     5011      +17     

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• ✅ login: xiaoxiaojx / name: xiaoxiaojx (4bc8cc648a07d769a11250f667cd5b66251e661b)

Merging this PR will not alter performance

⚡ 5 improved benchmarks
❌ 7 regressed benchmarks
✅ 132 untouched benchmarks
⏩ 72 skipped benchmarks¹

Performance Changes

_{Comparing feat/static-export-bindings (ed29f43) with main (1a17812)}

@xiaoxiaojx Looks like we need to make rebase

@alexander-akait Yeah, let’s merge #20973 first. Looks like both PRs need the ConstValuePlugin logic, so we can reuse it after the merge.

@xiaoxiaojx merged, feel free to rebase

Types Coverage

@alexander-akait, @xiaoxiaojx

Optimization rules:
Only const declarations are eligible (function/class names can be reassigned in sloppy mode)

I'm not sure what 'sloppy mode' is, but (1) can this be toggled on/off with a webpack config setting, and (2) can you detect that it is off and so enable function and class names in this optimization? I feel that many more exports would fall into the class/function buckets and could benefit from this optimization.

Good question! The "sloppy mode" comment in the code is actually slightly misleading — I'll fix that. The real reason is that function and class declarations create mutable bindings (like let), which can be reassigned even in strict mode (and ESM is always strict):

function fn() { return 1; }
fn = 2; // valid in strict mode
export { fn }; // fn could be 2

Only const guarantees immutability at the language level, so it's the only safe case without additional analysis.

To answer your questions:

1. Toggle: Yes, this optimization is gated behind optimization.inlineExports (defaults to true in production).
2. Extending to function/class: Strict mode detection wouldn't help here since reassignment is valid in both modes. However, we could extend this in the future by statically analyzing whether a function/class name is never reassigned within the module — that would safely unlock value binding for those exports too.

@xiaoxiaojx Let's add a todo for this too in code/issue