feat(es/minifier): Invoke IIFE into block

[Austaras]

Description:

This is maybe the biggest missing feature of terser as compared to gcc because its lack of proper scope support. But we have.

Further development:

1. invoke IIFE with return into labelled break
2. invoke IIFE in place where value is needed like if (() => {} ())
3. invoke IIFE in seq and other side effect free expressions

Related issue:

• Closes es/minifier: deep inline functions with statements #10054

[changeset-bot]

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Latest commit: 39e6480

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[codspeed-hq]

CodSpeed Performance Report

Merging #10220 will degrade performances by 2.08%

_{Comparing Austaras:main (39e6480) with main (482b63a)}

Summary

⚡ 2 improvements
❌ 1 regressions
✅ 149 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
❌	serialization of serde	2.8 µs	2.8 µs	-2.08%
⚡	es/lints/libs/d3	28.2 ms	27.8 ms	+1.24%
⚡	es/lints/libs/terser	29.7 ms	29 ms	+2.49%

[kdy1]

I'll review this very carefully with some time. Sorry for the delay, but this is a quite advanced optimization.

[Copilot]

Pull Request Overview

This PR implements changes to invoke IIFE blocks into a new block structure for various module outputs and async/await helper functions. The key changes include:

• Updating snapshot test outputs for library sizes.
• Rewriting module export patterns (AMD, CommonJS, UMD) to use a variable assignment with an "all" object and a for‑in loop.
• Modifying async/await helper output by removing IIFE wrappers.

Reviewed Changes

Copilot reviewed 160 out of 160 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
crates/swc/tests/libs-size.snapshot.md	Updated size snapshot values for various libraries.
crates/swc/tests/tsc-references/contextuallyTypedStringLiteralsInJsxAttributes02.2.minified.js	Reordered export definitions with new function declarations.
crates/swc/tests/tsc-references/exportAsNamespace3(module=amd).2.minified.js	Changed export pattern to use an "all" object and for‑in loop.
crates/swc/tests/tsc-references/exportAsNamespace2(module=amd).2.minified.js	Changed export pattern to use an "all" object and for‑in loop.
crates/swc/tests/tsc-references/asyncAwaitIsolatedModules_es6.2.minified.js	Removed IIFE wrapper in async/await helper function assignment.
crates/swc/tests/tsc-references/asyncAwaitIsolatedModules_es5.2.minified.js	Removed IIFE wrapper in async/await helper function assignment.
crates/swc/tests/tsc-references/asyncAwait_es6.2.minified.js	Removed IIFE wrapper in async/await helper function assignment.
crates/swc/tests/tsc-references/asyncAwait_es5.2.minified.js	Removed IIFE wrapper in async/await helper function assignment.
crates/swc/tests/tsc-references/exportAsNamespace2(module=umd).2.minified.js	Changed export pattern to use an "all" object and for‑in loop.
crates/swc/tests/tsc-references/exportAsNamespace2(module=commonjs).2.minified.js	Changed export pattern to use an "all" object and for‑in loop.
crates/swc/tests/tsc-references/exportAsNamespace3(module=commonjs).2.minified.js	Changed export pattern to use an "all" object and for‑in loop.
crates/swc/tests/tsc-references/exportAsNamespace3(module=umd).2.minified.js	Changed export pattern to use an "all" object and for‑in loop.
crates/swc/tests/tsc-references/amdImportNotAsPrimaryExpression.2.minified.js	Changed export pattern; removal of a redundant variable declaration.
crates/swc/tests/tsc-references/commonJSImportNotAsPrimaryExpression.2.minified.js	Changed export pattern; removal of redundant declaration ordering.
crates/swc/tests/tsc-references/declarationEmitThisPredicates01.2.minified.js	Changed export pattern to use variable assignment and "all" object.
crates/swc/tests/tsc-references/assignmentCompatWithDiscriminatedUnion.2.minified.js	Updated call ordering within expression chains.
crates/swc/tests/tsc-references/emptyVariableDeclarationBindingPatterns01_ES6.2.minified.js	Modified scope and declaration patterns in for‑of loops.
crates/swc/tests/tsc-references/exportAsNamespace1(module=amd).2.minified.js	Changed export pattern to use an "all" object and for‑in loop.
crates/swc/tests/tsc-references/exportAsNamespace1(module=commonjs).2.minified.js	Changed export pattern to use an "all" object and for‑in loop.
crates/swc/tests/tsc-references/exportAsNamespace1(module=umd).2.minified.js	Changed export pattern to use an "all" object and for‑in loop.

Comments suppressed due to low confidence (2)

crates/swc/tests/tsc-references/amdImportNotAsPrimaryExpression.2.minified.js:14

• The function for property 'E1' returns 'E11', which is not defined. This may cause a runtime error.

E1: function() { return E11; }

crates/swc/tests/tsc-references/commonJSImportNotAsPrimaryExpression.2.minified.js:10

• The function for property 'E1' returns 'E11', which is not defined. This may cause a runtime error.

E1: function() { return E11; }

[kdy1]

Note from copilot:

The initialization order of the variables (Example1, Example2, Example3, Example4, Example5, GH14865, GH30170, GH12052, GH18421, GH15907, GH20889, and GH39357) remains the same before and after the changes. The primary difference is the movement of the getAxisType function call and the removal of a few lines, which does not affect the order of variable initialization.

[kdy1]

What about the finally block?

[Austaras]

finally block, despite run after every throw, would not change control flow, following code would not be executed if there's no catch

[Copilot]

Pull Request Overview

This PR implements a new feature in the ES minifier to invoke IIFEs into blocks, addressing missing scope support compared to gcc. The changes include refactoring how IIFEs and export objects are wrapped across various module formats (AMD, CommonJS, UMD) and updating snapshot files to reflect the new minified output.

• Export object definitions are refactored to use a local “all” variable with an iteration to define properties.
• The IIFE invocation for functions (e.g. for f1) is updated to use block scoping via immediate object assignment.
• Snapshot files are updated to reflect minor size changes.

Reviewed Changes

Copilot reviewed 164 out of 164 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
crates/swc/tests/libs-size.snapshot.md	Updated snapshot output values for compressed and gzipped sizes.
crates/swc/tests/tsc-references/contextuallyTypedStringLiteralsInJsxAttributes02.2.minified.js	Reordered export definitions and function declarations for clarity.
crates/swc/tests/fixture/issues-4xxx/4953/output/index.js	Wrapped the export assignment of “vr” in an IIFE to enforce strict mode.
Multiple files under crates/swc/tests/tsc-references/	Standardized export object creation across AMD, CommonJS, and UMD modules; updated async/await patterns accordingly.
crates/swc/tests/tsc-references/emptyVariableDeclarationBindingPatterns01_ES6.2.minified.js	Adjusted loop binding declarations (using const over let) in destructuring loops.

Comments suppressed due to low confidence (1)

crates/swc/tests/tsc-references/amdImportNotAsPrimaryExpression.2.minified.js:15

• The getter for E1 returns E11, which appears to be undefined; please verify whether it should return E1 instead.

return E11;