fix(codegen): preserve quotes for cjs-module-lexer equality strings by Dunqing · Pull Request #22551 · oxc-project/oxc

Dunqing · 2026-05-19T03:54:06Z

Summary

Force plain string quotes for "default" / "__esModule" operands of ==/===/!=/!== during minification, so cjs-module-lexer can recognise the Object.keys(mod).forEach(key => key === "default" || ...) re-export filter emitted by Babel / TypeScript / Rollup.
Follow-up to fix(codegen): preserve string quotes in require() calls during minification #22475 (which fixed require("…")). Same root cause: calculate_quote_maybe_backtick's equal-cost tie-breaker prefers backtick, which the lexer's heuristic parser doesn't accept.
Caught by monitor-oxc's whitespace runner: minifying @babel/types/lib/index.js previously broke import { isIdentifier } from "@babel/types" under --experimental-require-module. Raw minified size is unchanged across all minsize fixtures.

Example

Input:

Object.keys(mod).forEach(function (key) {
  if (key === "default" || key === "__esModule") return;
});

Before (broken — cjs-module-lexer skips the re-export):

Object.keys(t).forEach(function(e){if(e===`default`||e===`__esModule`)return});

After:

Object.keys(t).forEach(function(e){if(e==="default"||e==="__esModule")return});

AI disclosure: drafted with Claude Code, reviewed manually.

Dunqing · 2026-05-19T03:54:22Z

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codspeed-hq · 2026-05-19T04:01:28Z

Merging this PR will not alter performance

✅ 48 untouched benchmarks
⏩ 3 skipped benchmarks¹

_{Comparing fix/codegen-cjs-lexer-equality-strings (1fcdf7f) with main (87f065e)²}

3 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩
No successful run was found on main (ec7de07) during the generation of this report, so 87f065e was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

camc314

@Dunqing should we also PR upstream to add support for backticks?

Dunqing · 2026-05-19T07:34:19Z

@Dunqing should we also PR upstream to add support for backticks?

That would be good, but I'm not sure if they will accept these 😢

camc314 · 2026-05-19T07:40:33Z

Ah this is frustrating:

Detection patterns for this project are frozen. This is because adding any new export detection patterns would result in fragmented backwards-compatibility. Specifically, it would be very difficult to figure out why an ES module named export for CommonJS might work in newer Node.js versions but not older versions. This problem would only be discovered downstream of module authors, with the fix for module authors being to then have to understand which patterns in this project provide full backwards-compatibily. Rather, by fully freezing the detected patterns, if it works in any Node.js version it will work in any other. Build tools can also reliably treat the supported syntax for this project as a part of their output target for ensuring syntax support.

graphite-app · 2026-05-19T08:42:11Z

Merge activity

May 19, 8:42 AM UTC: Dunqing added this pull request to the Graphite merge queue.
May 19, 8:47 AM UTC: Merged by the Graphite merge queue.

…22551) ## Summary - Force plain string quotes for `"default"` / `"__esModule"` operands of `==`/`===`/`!=`/`!==` during minification, so `cjs-module-lexer` can recognise the `Object.keys(mod).forEach(key => key === "default" || ...)` re-export filter emitted by Babel / TypeScript / Rollup. - Follow-up to #22475 (which fixed `require("…")`). Same root cause: `calculate_quote_maybe_backtick`'s equal-cost tie-breaker prefers backtick, which the lexer's heuristic parser doesn't accept. - Caught by monitor-oxc's `whitespace` runner: minifying `@babel/types/lib/index.js` previously broke `import { isIdentifier } from "@babel/types"` under `--experimental-require-module`. Raw minified size is unchanged across all `minsize` fixtures. ## Example Input: ```js Object.keys(mod).forEach(function (key) { if (key === "default" || key === "__esModule") return; }); ``` Before (broken — `cjs-module-lexer` skips the re-export): ```js Object.keys(t).forEach(function(e){if(e===`default`||e===`__esModule`)return}); ``` After: ```js Object.keys(t).forEach(function(e){if(e==="default"||e==="__esModule")return}); ``` AI disclosure: drafted with Claude Code, reviewed manually.

…le (#22552) ## Summary - Move all four `try_print_cjs_*` helpers — `require("…")`, `Object.defineProperty(_, "name", …)`, `exports[STR] = …`, and `key === "default"` / `key === "__esModule"` — into a new `cjs_module_lexer` module. - Add a module-level doc explaining the shared root cause (`calculate_quote_maybe_backtick`'s backtick tie-breaker that the lexer's heuristic parser doesn't accept) and listing all four positions in one table, so the next workaround has an obvious home. - Names drop the redundant `cjs_` prefix; call sites use `cjs_module_lexer::try_print_…`. No behavior change. Stacked on top of #22551. AI disclosure: drafted with Claude Code, reviewed manually.

### 🚀 Features - e857b0c napi/minify: Expose legalComments option and result (#20370) (Boshen) - 661132d parser: More friendly error messages for rest assignment target and rest binding element (#22719) (sapphi-red) - ee659b6 transformer/legacy-decorator: Add `strictNullChecks` option for nullable-union design:type (#22266) (Kyle Cannon) ### 🐛 Bug Fixes - e1d064e transformer/class-properties: Reparent lifted private method helpers (#22716) (Cameron) - 4ac0fca minifier: Preserve `0 && (module.exports = { ... })` cjs-module-lexer hint (#22729) (Dunqing) - 40ff611 minifier: Mark peephole loop changed when dropping dead-after-throw statement (#22722) (Dunqing) - 2f7b210 codegen: Emit pife-arrow/function leading comments inside the wrap (#22720) (Dunqing) - e184f74 parser: Improve invalid `import` property access diagnostic (#22693) (camc314) - 7baed9c transformer/private-method: Clear inherited strict flags (#22508) (camc314) - a9ad27e parser: Keep annotation comments leading without preceding newline (#22711) (Dunqing) - 9ea4d64 minifier: Re-evaluate pure/no-side-effects flags after peephole inlining (#22595) (Dunqing) - 07afbb6 minifier: Drop empty-body IIFE wrapper when called with arguments (#22589) (Dunqing) - fa7c463 semantic: Correct TS enum member symbol spans (#22689) (camc314) - 26b9396 semantic: Resolve parameter decorators outside parameter scope (#22623) (camc314) - b284045 parser: Switch to module goal eagerly on `export` (#22684) (Boshen) - dfa931d semantic: Propagate unresolved auto-increment enum value instead of defaulting to 0 (#22646) (Dunqing) - 69a6ba6 transformer/legacy-decorator: Emit Array for ReadonlyArray<T> in decorator metadata (#22265) (Kyle Cannon) - e421ef0 transformer/legacy-decorator: Return runtime binding for design:type (#22640) (Dunqing) - d61e1d7 codegen: Preserve verbatim text of pure/no-side-effects comments (#22525) (Dunqing) - 702b14e minifier: Preserve IIFE structure in DCE-only mode (#22547) (Dunqing) - 917da24 parser: Apply PURE comment through member-access chains (#22566) (Dunqing) - a069b1c codegen: Preserve quotes for cjs-module-lexer equality strings (#22551) (Dunqing) ### ⚡ Performance - 2f623b0 semantic: Skip unresolved checks for re-exports (#22660) (camc314) - 0d9553d semantic: Early-exit `check_object_expression` for objects with <2 properties (#22668) (Dunqing) - d721ad9 semantic: Use direct grandparent lookup for TS type parameters (#22658) (camc314) - 0aff288 semantic: Reorder numeric literal strict mode checks (#22657) (camc314) - 4d5ddb1 semantic: Reorder binding identifier checks (#22656) (camc314) - e32acd8 semantic: Reorder identifier ambient binding check (#22653) (camc314) - 09fe178 semantic: Reorder ident reference strict mode check (#22652) (camc314) - 4b6add2 semantic: Avoid duplicate ident clone for bindings (#22663) (camc314) - 82f9662 parser: Check identifier kind before context flag (#22662) (camc314) - d7cd951 parser: Fast path identifier parsing and inline operator helpers (#22650) (Boshen) - 7b84314 semantic: Use direct byte access for numeric leading-zero check (#22642) (camc314) - 0345a31 semantic: Pre-size class elements hash map (#22618) (camc314) - 04d3065 minifier: Drop per-call buffers in try_fold_concat (#22596) (Dunqing) - 4f289f1 semantic: Resolve_references_for_current_scope without a temp Vec (#22599) (Dunqing) - e862c15 semantic: Avoid heap alloc for var hoist scope ids (#22603) (Dunqing) - 8ff8674 semantic: Early return if `excess` is `0` in `Stats::increase_by` (#22616) (camc314) - 7a4120e semantic: Pre-reserve unresolved_references using Stats::references (#22580) (Dunqing) Co-authored-by: Dunqing <29533304+Dunqing@users.noreply.github.com>

github-actions Bot added the A-codegen Area - Code Generation label May 19, 2026

Dunqing mentioned this pull request May 19, 2026

refactor(codegen): consolidate cjs-module-lexer helpers into one module #22552

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Dunqing marked this pull request as ready for review May 19, 2026 04:17

camc314 reviewed May 19, 2026

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camc314 approved these changes May 19, 2026

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graphite-app Bot added the 0-merge Merge with Graphite Merge Queue label May 19, 2026

graphite-app Bot force-pushed the fix/codegen-cjs-lexer-equality-strings branch from 1fcdf7f to a069b1c Compare May 19, 2026 08:43

graphite-app Bot merged commit a069b1c into main May 19, 2026
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graphite-app Bot removed the 0-merge Merge with Graphite Merge Queue label May 19, 2026

graphite-app Bot deleted the fix/codegen-cjs-lexer-equality-strings branch May 19, 2026 08:47

oxc-guard Bot mentioned this pull request May 26, 2026

release(crates): oxc v0.133.0 #22734

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fix(codegen): preserve quotes for cjs-module-lexer equality strings#22551

fix(codegen): preserve quotes for cjs-module-lexer equality strings#22551
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fix/codegen-cjs-lexer-equality-strings

Dunqing commented May 19, 2026 •

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Dunqing commented May 19, 2026

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Merging this PR will not alter performance

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Dunqing commented May 19, 2026 •

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