perf(transformer): pre-size statement vecs in TS enum & namespace lowering#23516
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…ering Two zero-capacity arena `Vec`s were filled in known-length loops and grew via reallocation. Pre-size them, mirroring the JSX-props pre-size (oxc-project#23466): - `transform_ts_enum_members`: emits exactly `members.len() + 1` statements (one per member + the final `return`) — an exact capacity. - TS namespace `enter_program`: rebuilds the program body; pre-size to `program.body.len()` (an estimate — most statements pass through 1:1). Behaviour-preserving (capacity-only; contents and push order unchanged). `allocs_transformer.snap` reallocations drop on the TS fixtures: checker.ts 64->5, binder.ts 6->0, App.tsx 25->17, kitchen-sink.tsx 304->280.
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### 💥 BREAKING CHANGES - 7a76cd3 estree: [**BREAKING**] Make whether to include TS fields a runtime option (#23574) (overlookmotel) - e7b6b68 estree: [**BREAKING**] `ESTree` config use methods not consts (#23573) (overlookmotel) ### 🚀 Features - 556cc6d data_structures: Add `CodeBuffer::as_str` method (#23571) (overlookmotel) - 38c4b06 parser: Add friendly error for adjacent JSX elements (#23378) (sapphi-red) - 53509a8 minifier: Treeshake pure typed arrays and Set/Map array literals (#23469) (Dunqing) - 09762d9 minifier: Inline const value for read-only vars (#22593) (Dunqing) ### 🐛 Bug Fixes - 20375f9 react_compiler: Keep imports referenced only by a computed key (#23586) (Boshen) - 31bfd9b minifier: Keep Object introspection calls on a possible Proxy (#23483) (Dunqing) - 837a395 parser: Treat a line comment after ':' as leading, not trailing (#23515) (Dunqing) - e409fe0 minifier: Keep `new Map`/`WeakSet`/`WeakMap` with a string argument (#23470) (Dunqing) - ae02b4e ci/parser: Use `minimal` for vitest reporter (#23457) (camc314) ### ⚡ Performance - cf24329 mangler: Compile slot sort once instead of per CAPACITY (#23577) (Boshen) - 4058a6a parser: Reduce code bloat from verify_modifiers monomorphization (#23576) (Boshen) - 053b0c1 estree: Remove pointless `mem::take` (#23572) (overlookmotel) - dfb52b6 transformer: Pre-size statement vecs in TS enum & namespace lowering (#23516) (Yunfei He) - 970e09a minifier: Compute template-literal inline checks in a single pass (#23467) (Yunfei He) - 3170c0e semantic,mangler,minifier: Fix `Semantic::stats` node count and reuse stats in mangler builds (#23352) (Boshen) - d1fa6e0 minifier: Evaluate ternary branches once in minimize_conditional_expression (#23479) (Yunfei He) - 3fa8051 transformer: Pre-size JSX props vec to attribute count (#23466) (Yunfei He) - 488b382 react_compiler: Borrow binding names in prefilter instead of allocating (#23471) (Yunfei He) - bcb3894 minifier: Incremental scoping refresh, delete LiveUsageCollector (#23197) (Dunqing) ### 📚 Documentation - f68641e data_structures: Improve docs on safety contract (#23575) (overlookmotel) Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>
camc314
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…ering (#23516) ## What Two zero-capacity arena `Vec`s in the TypeScript transformer were filled in known-length loops and grew via reallocation. Pre-size them — mirroring the JSX-props pre-size in #23466: - **`transform_ts_enum_members`**: emits exactly `members.len() + 1` statements (one per member + the final `return`) → `vec_with_capacity(members.len() + 1)` (an **exact** capacity). - **TS namespace `enter_program`**: rebuilds the program body; pre-size to `program.body.len()` (an estimate — most statements pass through 1:1). ## Δ — fewer reallocations on TS fixtures `allocs_transformer.snap`, reallocation count: | fixture | before | after | | --- | --- | --- | | checker.ts | 64 | **5** | | kitchen-sink.tsx | 304 | **280** | | App.tsx | 25 | **17** | | binder.ts | 6 | **0** | (allocation **count** and **bytes** are unchanged — this removes the intermediate growth reallocations.) ## Why it is behavior-preserving Capacity-only: `vec_with_capacity` differs from `vec` solely in initial capacity; element type, push order, and contents are identical, so the produced AST is byte-identical. `oxc_transformer` tests pass. Prepared with AI assistance.
camc314
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Jul 3, 2026
### 💥 BREAKING CHANGES - 7a76cd3 estree: [**BREAKING**] Make whether to include TS fields a runtime option (#23574) (overlookmotel) - e7b6b68 estree: [**BREAKING**] `ESTree` config use methods not consts (#23573) (overlookmotel) ### 🚀 Features - 556cc6d data_structures: Add `CodeBuffer::as_str` method (#23571) (overlookmotel) - 38c4b06 parser: Add friendly error for adjacent JSX elements (#23378) (sapphi-red) - 53509a8 minifier: Treeshake pure typed arrays and Set/Map array literals (#23469) (Dunqing) - 09762d9 minifier: Inline const value for read-only vars (#22593) (Dunqing) ### 🐛 Bug Fixes - 20375f9 react_compiler: Keep imports referenced only by a computed key (#23586) (Boshen) - 31bfd9b minifier: Keep Object introspection calls on a possible Proxy (#23483) (Dunqing) - 837a395 parser: Treat a line comment after ':' as leading, not trailing (#23515) (Dunqing) - e409fe0 minifier: Keep `new Map`/`WeakSet`/`WeakMap` with a string argument (#23470) (Dunqing) - ae02b4e ci/parser: Use `minimal` for vitest reporter (#23457) (camc314) ### ⚡ Performance - cf24329 mangler: Compile slot sort once instead of per CAPACITY (#23577) (Boshen) - 4058a6a parser: Reduce code bloat from verify_modifiers monomorphization (#23576) (Boshen) - 053b0c1 estree: Remove pointless `mem::take` (#23572) (overlookmotel) - dfb52b6 transformer: Pre-size statement vecs in TS enum & namespace lowering (#23516) (Yunfei He) - 970e09a minifier: Compute template-literal inline checks in a single pass (#23467) (Yunfei He) - 3170c0e semantic,mangler,minifier: Fix `Semantic::stats` node count and reuse stats in mangler builds (#23352) (Boshen) - d1fa6e0 minifier: Evaluate ternary branches once in minimize_conditional_expression (#23479) (Yunfei He) - 3fa8051 transformer: Pre-size JSX props vec to attribute count (#23466) (Yunfei He) - 488b382 react_compiler: Borrow binding names in prefilter instead of allocating (#23471) (Yunfei He) - bcb3894 minifier: Incremental scoping refresh, delete LiveUsageCollector (#23197) (Dunqing) ### 📚 Documentation - f68641e data_structures: Improve docs on safety contract (#23575) (overlookmotel) Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>
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What
Two zero-capacity arena
Vecs in the TypeScript transformer were filled in known-length loops and grew via reallocation. Pre-size them — mirroring the JSX-props pre-size in #23466:transform_ts_enum_members: emits exactlymembers.len() + 1statements (one per member + the finalreturn) →vec_with_capacity(members.len() + 1)(an exact capacity).enter_program: rebuilds the program body; pre-size toprogram.body.len()(an estimate — most statements pass through 1:1).Δ — fewer reallocations on TS fixtures
allocs_transformer.snap, reallocation count:(allocation count and bytes are unchanged — this removes the intermediate growth reallocations.)
Why it is behavior-preserving
Capacity-only:
vec_with_capacitydiffers fromvecsolely in initial capacity; element type, push order, and contents are identical, so the produced AST is byte-identical.oxc_transformertests pass.Prepared with AI assistance.