fix(es/compat): Apply Array.prototype.slice to arguments in loose spread
#11122
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CodSpeed Performance ReportMerging #11122 will not alter performanceComparing Summary
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Pull Request Overview
This PR fixes the handling of the arguments object in loose spread transformations for ES2015 compatibility. The fix ensures that when arguments is used in a spread expression, it is properly converted using Array.prototype.slice.call(arguments) to create a real array before spreading.
- Adds special handling for the
argumentsidentifier in spread expressions - Transforms
...argumentsto useArray.prototype.slice.call(arguments)for proper array conversion
Reviewed Changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| crates/swc_ecma_compat_es2015/src/spread.rs | Implements special case handling for arguments in spread expressions by wrapping it with Array.prototype.slice.call() |
| crates/swc/tests/fixture/issues-10xxx/11118/input/index.js | Test input file demonstrating spread usage with arguments |
| crates/swc/tests/fixture/issues-10xxx/11118/input/.swcrc | Test configuration with loose mode enabled |
| crates/swc/tests/fixture/issues-10xxx/11118/output/index.js | Expected output showing proper transformation to Array.prototype.slice.call(arguments) |
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| let expr = match *expr { | ||
| Expr::Ident(Ident { ref sym, .. }) if &**sym == "arguments" => { |
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[nitpick] Consider extracting the string literal 'arguments' into a constant to avoid magic strings and improve maintainability.
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Pull Request Overview
Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.
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| @@ -0,0 +1,7 @@ | |||
| function xxx() { | |||
| var b = [].concat(Array.prototype.slice.call(arguments)); | |||
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Babel optimizes away the [].concat here. We can iterate on a refinement later.
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Pull Request Overview
Copilot reviewed 13 out of 13 changed files in this pull request and generated 1 comment.
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Description:
BREAKING CHANGE:
Related issue (if exists):